OpenURL to dial telephone number does not work with *67?

I am trying to add calling functionality to my application but one of the requirements is to add *67 before the phone number to block the caller ID. Unfortunately OpenURL will not execute the command, I guess because the string passed in is not a valid telephone number because of the *? Has anyone had any issues with this or is this just a bug?

var rawNumber = '5554443333';
Titanium.Platform.openURL('tel:*67' + rawNumber);