Redmine

hi, i'm doing a plugin for upload files, but after upload i have to validate some fields and if don't pass de validation come back to the create page keeping the introduced dates, so the user can change the wrongs date without itroduce all again, my problem is that i can keep all the dates less the file, and i'd like keep it too, any idea?

the code of the controller for keep dates:

def new

@document = AlfrescoDocument.new(params[:document])      
    @document.project_id = @project.id
    @edit_metadata = false
    @file=Tempfile.new(params[:file])
    @metadata = AlfrescoMetadata.new(params[:metadata])
    .....

and in the view the file is loaded with:

<p>
<label><%=l(:label_attachment)%><span class="required">*</label>
<%= file_field_tag 'file', :size => 30, :id => nil -%>
</p>

thanks.