Exchange Out of Office URL and DNS

Hello Experts - I'm working on a way to have my ActiveSync users be able to seamlessly  transition from outside the office on 3G to inside the office on an internal private wireless network.  The problem is name resolution.  Outside the office they are using this address:

https://exchange.company.org/owa

Internally they are using this address:

https://internalservername.comain.local.owa

I had setup a DNS entry last week which allowed the first address to resolve to the internal address and that works except doing so breaks the users ability to set out of office messages.  When using the internal wireless network the users would get an error saying the server can't be reached.  I investigated and found that Outlook uses a URL to set the OOF messages which can be seen by holding control, clicking the Outlook 2010 icon, then selecting Test E-mail AutoConfiguration.

Is there a way out of this conundrum?  I have two exchange servers setup in a DAG, I was thinking of changing the OOF URL to point to the second server who's name should resolve properly both internally and externally as its offsite but I wasn't positive this will work.  I'd appreciate any advice!