Setting alternate reply address for exchange gmail sync

[kirstein]

I know similar questions have been asked before, but I'm going to try this out anyway.

I have a mail business email account, and a gmail account. I want to use my gmail account as a "cache" for all my email on my phone and sync via exchange to gmail. Forward my mail to gmail, when I reply I reply through gmail So far so good.

In Gmail you can now set it up so your replies appear to have been sent from your alternate email address. Perfect. I've tried it and it works correctly from their webmail platform. However, any replies sent from my phone still appear to have been sent from the gmail address. That's a dealbreaker.

Is there any way to change the "from" address on mail sent from my phone on an gmail exchange account?
I'm using WM 6.5 (Mightyrom) on a TP2.

Thanks in advance.