[SM-PLUGINS] Procmail pluginin virtual environment?

[Rob B. <br...@cs...>]

I am running Squirrelmail in a virtual environment, where the mail
users all share a single unix user name and password, and log in
with their full email address.

I've installed the procmail filter, and when trying to create a
filter I get the error:

Warning:  ftp_login(): Login incorrect. in
/usr/share/squirrelmail/plugins/procfilter/procfilter_options.php
on line 187
Warning:  ftp_put(): Please login with USER and PASS. in
/usr/share/squirrelmail/plugins/procfilter/procfilter_options.php
on line 188

Which makes sense since the user I'm logged in as in Squirrelmail
doesn't have a unix account.

Is this a known limitation of the procmail filter plugin?  Or is
there some workaround?

TIA

Rob