I tried this several times but with no luck.
the ordinary syntax for
mailto links is like a ordinary url
first parameter starts with a ? next parameter and so with & nothing complicated here
mailto:emailadress
creates a new email with the default client
mailto:emailadress?subject=My email
Created a new email and the subject is my Email
mailto:emailadress?subject=My email&body=some text
Same as above but with "some text" in the body field
mailto:emailadress?subject=My email&body=some text&attach=c:\tempfile.txt
Same as above but you will also automatic attach the file tempfile.txt
most of the examples that is shown on the net is for outlook and they use another parameter name &attachments= this doesn't work with Lotus Notes
You can also use cc and bcc to add people in these fields automatically.