[Seaside] MIME documents

[Brian Murphy-Dye]

The following code allows the web client to download comma separated  
data.

html anchor
     document: (self csvData asMIMEDocumentType: 'text/csv')
     mimeType: 'text/csv'
     fileName: 'ctaexport-' , Date today yyyymmdd , '-' , Time now  
hhmm24 , '.csv';
     text: 'Export (csv)'.

My problem is that the MIME document is created at render time, but  
the data I want sent is dependent upon the fields on the form. Anyone  
know of a convenient way to make the document be created after the  
link is clicked?

Thanks in advance, Brian.