I have the same issue and can't figure out how to fix it.
A s:link that should result in : http://www.myhost.com/root/LINK
is in fact :
/project/LINK in a generated email
/root/LINK in a generated pdf.
I've see that I can add the host in seam mail by adding
To sum it up : how to make s:link work as expected in email and pdf generated document ?