How to set default e-mail separate from account settings

[kruste]

So, here's the scoop. Our hosted Exchange moved domains and in the transfer it added some wacky new e-mail address as my default address, which is the "real" address for the host, but the one I want is an alias. Before the switch my iPhone e-mail account address was the alias. Now when I send mail I have to change the from e-mail to the alias address. Is there a way to tell my iPhone which of the three (yes, there's one more that was added with the same account) e-mail addresses to use as the default address?

Here's an example of what happened:

Before
-------------------
user@domain.com (default)

After
-------------------
user.domain@someotherdomain.com (default)
wackynumbers@wackydomain.com
user@domain.com

I want user@domain.com to be the default for this single account.