[c-nsp] can cisco pix "boomerang" mail traffic?

[Rogelio]

Can a Cisco PIX "boomerang" a packet--i.e. route a packet coming from 
the internal network that is destined for an Internet host back into
the internal network via NAT?

I ask because I have have email clients pointing to mail.domain.com, and 
unless I do a split DNS with my mail A record pointing to a 192 address 
inside and an external mail A record pointing to my public IP address, 
I'm not quite sure how to do it.

Users using Microsoft Outlook + Exchange don't have a problem getting 
their email.  But users using other email clients (Thunderbird, Outlook 
Express, etc) obviously cannot resolve the host name if they are on the 
wrong side of the network.  Thunderbird has different identities for 
each email account, but that's too much work for some of the users.