it possible to add gmail as my second exchange account on my iphone 5

I have my coporate account as an exchange account on my Iphone 5, hotmail and Gmail. My problem is that Gmail not setup as an exchnage account won't sync contacts and won't push email which is no fun at all.

When i try to add a second exchange account (my gmail) everything is fine until I go to my Mailbox and I get an error message telling me unable to connect to server?

Is my corporate certificat blocking the possibility of having a second exchange account or AM I forgetting something?

Thanks in advance.

Mat