sNAT with irules?

Hey guys I have a question for you. I have a pool of mail servers. These servers send mail to a server outside of the LTM for scanning purposes. These servers must all apear as the same source address lets say 1.1.1.5. Easy enough, I put them in a sNAT pool. Now here is the problem. These servers must communicate with an AV (anti-virus) console 2.2.2.10 for updates. The servers of course always appear to the console as 1.1.1.5 because of the sNAT. Now because of this once the first server gets his AV update the console thinks the address has already been updated and never tries to update the others... I would assume I am going to have to get rid of the sNAT and create some type of iRule for this but I am new to this. So, any insight you guys have would be greatly appreciated.