Extension list

I need to setup a user’s extension such that it goes to his cell phone number if he does not answer.

Assuming that:
a. The cell phone number is 5551212
b. To get an outside line you need to dial 99 and wait for the external dial tone

In freePBX -> Follow Me -> extension list
the
995551212#
entry does not work.

This is because there is no waiting for the external dial tone after 99

How do I add a delay between 99 and 5551212#

According to:
voip-info.org/wiki/view/Asterisk+cmd+Dial

“…If you need a .5 second pause while dialing a number you can insert a w in the appropriate place…”

So I tied
99ww5551212#
and
99w5551212#

But freePBX does not like it and cleans it up by removing the w in both cases.

Any suggestions?