Only show payment method when UPS shipping method chosen?

I'm trying to figure out how to limit the payment methods shown depending on the shipping method chosen at checkout (step 1), but I can't figure out what's wrong.

After scouring the boards, it seems like this should be correct.. but the payment methods still shows up in checkout regardless of the shipping method I chose.

ex: cc.php line 56

	 //  Only allow orders when ship by upsxml
if ($_SESSION['shipping']['title'] = 'upsxml') 	{ 
$this->enabled = ((MODULE_PAYMENT_CC_STATUS == 'True') ? true : false);
}

I tried switching upsxml with upsxml_upsxml and Flat Rate, but no change.

Any ideas?

Have you tried just $_SESSION['shipping']['id'] instead of ['title'] to it?

example using the ups.php shipping module:
$_SESSION['shipping']['title'] = United Parcel Service (1 x 11.10lbs) (3 Day Select)
$_SESSION['shipping']['id'] = ups_3DS

Also, if a module is turned off (ie: disabled or uninstalled) then it won't even be triggered for evaluation. You're better to have it enabled, and then have the code disable it if it doesn't apply.