[TxMt] Shell used by TM

So,

I've used DarwinPorts (aka MacPorts) to install the latest version of the BASH shell (v3.1.17). I've set it as my default shell within the NetInfo database. I also have it on the list of acceptable shells in my etc/shells file

I'm just wondering how you force TextMate to use this shell as opposed to the built-in BASH shell.

When ever I run (done by selecting the "Filter Through Command" menu item in the Text menu. I select input none, and am working in a blank document, and I select "Insert as Text" as the output): echo $BASH_VERSION I get back: 2.05b.0(1)-release

In the terminal I get: 3.1.17(1)-release

Can anyone help?

-Brian