Adding dial pause and code to follow me

I tried searching the forums for a solution to this dilemma, but I’m hoping someone here can clarify…here’s my situation.

I have system on our new phone server, feeding Grandstream GXP2110s and the like. Our PRI runs through a 3rd party vendor who requires us to enter in a 3 digit code for long distance calls for billing purposes.

I have one user who has a long distance cell phone number and I cannot for the life of me get the Follow Me feature to dial his cell phone because the PRI vendor wants that 3 digit code…how do I program the follow me line to insert the required pause for the PRI to pickup the code?

I’ve tried 15555553904#ww354 but it strips the “ww” when I submit. Am I just off my rocker or is this not possible?

As far as I can tell, the only addon module I have is Custom Contexts v2.8.0rc1.1

Thanks in advance for any help you can provide.