How to reply with a different email address? - Gmail Sync

[WhiteWidow]

Loving the new gmail sync but here is my issue. I have my gmail account I use for family and friends, then I have my work account forwarded to my gmail account. I have my work account set up in gmail to be able to sent through it. Works fine via gmail on my computer, but how do I choose how to send mail from a different account. When I reply to a work mail account email it sends as my gmail account and cc's my work account so then I get a copy of what I just sent. Any ideas how to send and reply from my work account? I think somehow gmail should see that I have sending from my work account enabled and route it accordingly.