diff -ur ../tmp/redmine-1.0.1/app/models/mailer.rb ./app/models/mailer.rb
--- ../tmp/redmine-1.0.1/app/models/mailer.rb	2010-08-19 06:30:23.000000000 +0200
+++ ./app/models/mailer.rb	2010-09-04 19:56:32.000000000 +0200
@@ -40,6 +40,7 @@
                     'Issue-Id' => issue.id,
                     'Issue-Author' => issue.author.login
     redmine_headers 'Issue-Assignee' => issue.assigned_to.login if issue.assigned_to
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", issue.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     message_id issue
     recipients issue.recipients
     cc(issue.watcher_recipients - @recipients)
@@ -60,6 +61,7 @@
                     'Issue-Id' => issue.id,
                     'Issue-Author' => issue.author.login
     redmine_headers 'Issue-Assignee' => issue.assigned_to.login if issue.assigned_to
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", issue.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     message_id journal
     references issue
     @author = journal.user
@@ -94,6 +96,7 @@
   #   Mailer.deliver_document_added(document) => sends an email to the document's project recipients
   def document_added(document)
     redmine_headers 'Project' => document.project.identifier
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", document.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     recipients document.recipients
     subject "[#{document.project.name}] #{l(:label_document_new)}: #{document.title}"
     body :document => document,
@@ -125,6 +128,7 @@
       recipients container.recipients
     end
     redmine_headers 'Project' => container.project.identifier
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", container.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     subject "[#{container.project.name}] #{l(:label_attachment_new)}"
     body :attachments => attachments,
          :added_to => added_to,
@@ -139,6 +143,7 @@
   #   Mailer.deliver_news_added(news) => sends an email to the news' project recipients
   def news_added(news)
     redmine_headers 'Project' => news.project.identifier
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", news.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     message_id news
     recipients news.recipients
     subject "[#{news.project.name}] #{l(:label_news)}: #{news.title}"
@@ -155,6 +160,7 @@
   def message_posted(message)
     redmine_headers 'Project' => message.project.identifier,
                     'Topic-Id' => (message.parent_id || message.id)
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", message.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     message_id message
     references message.parent unless message.parent.nil?
     recipients(message.recipients)
@@ -173,6 +179,7 @@
   def wiki_content_added(wiki_content)
     redmine_headers 'Project' => wiki_content.project.identifier,
                     'Wiki-Page-Id' => wiki_content.page.id
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", wiki_content.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     message_id wiki_content
     recipients wiki_content.recipients
     cc(wiki_content.page.wiki.watcher_recipients - recipients)
@@ -190,6 +197,7 @@
   def wiki_content_updated(wiki_content)
     redmine_headers 'Project' => wiki_content.project.identifier,
                     'Wiki-Page-Id' => wiki_content.page.id
+    from Setting.mail_from_pattern.to_s.gsub("%%projectid%%", wiki_content.project.identifier) unless Setting.mail_from_pattern.to_s.empty?
     message_id wiki_content
     recipients wiki_content.recipients
     cc(wiki_content.page.wiki.watcher_recipients + wiki_content.page.watcher_recipients - recipients)
diff -ur ../tmp/redmine-1.0.1/app/views/settings/_notifications.rhtml ./app/views/settings/_notifications.rhtml
--- ../tmp/redmine-1.0.1/app/views/settings/_notifications.rhtml	2009-12-19 21:07:09.000000000 +0100
+++ ./app/views/settings/_notifications.rhtml	2010-09-04 19:43:33.000000000 +0200
@@ -4,6 +4,8 @@
 <div class="box tabular settings">
 <p><%= setting_text_field :mail_from, :size => 60 %></p>
 
+<p><%= setting_text_field :mail_from_pattern, :size => 60 %></p>
+
 <p><%= setting_check_box :bcc_recipients %></p>
 
 <p><%= setting_check_box :plain_text_mail %></p>
diff -ur ../tmp/redmine-1.0.1/config/locales/en.yml ./config/locales/en.yml
--- ../tmp/redmine-1.0.1/config/locales/en.yml	2010-08-22 21:48:52.000000000 +0200
+++ ./config/locales/en.yml	2010-09-04 19:45:46.000000000 +0200
@@ -303,6 +303,7 @@
   setting_attachment_max_size: Attachment max. size
   setting_issues_export_limit: Issues export limit
   setting_mail_from: Emission email address
+  setting_mail_from_pattern: Emission email address pattern
   setting_bcc_recipients: Blind carbon copy recipients (bcc)
   setting_plain_text_mail: Plain text mail (no HTML)
   setting_host_name: Host name and path
diff -ur ../tmp/redmine-1.0.1/config/settings.yml ./config/settings.yml
--- ../tmp/redmine-1.0.1/config/settings.yml	2010-08-22 21:49:26.000000000 +0200
+++ ./config/settings.yml	2010-09-04 19:55:23.000000000 +0200
@@ -47,6 +47,11 @@
   default: '25,50,100'
 mail_from:
   default: redmine@example.net
+# pattern for From address
+# - can replace '%%projectid%%' with project ID
+# ex: %%projectid%%-support@example.net"
+mail_from_pattern:
+  default: ""
 bcc_recipients:
   default: 1
 plain_text_mail: