We ary trying to add our own content filter to our zimbra install.
Generally this is done with postfix but to do this we need postfix's
sendmail replacement/wrapper. I believe it is part of the standard
postfix install but. I cannot find it in the postfix files installed
with Zimbra.

Is there a reason for this? Any ideas on how to cleanly get it back
without any damage to the Zimbra install?

If we are successfull at getting TMDA working with Zimbra would you be interested in how it was done?