[Asterisk-Users] Speed Dial / New Context

[Asterisk]

I've been setting up a basic speed dial for sip users that don't have a
speed dial function on their phones (aastra 480i specifically, though I
think that it also affects grandstream)

So far so good - 

A) user can enter a specific extension, enter the 2 digit speed dial number,
and the target phone number
B) user can enter **xx (xx is the 2 digit speed dial) and the system makes
the call

However, I would like before * makes the call is to "pretend" that the
speeddial number has been entered directly from the phone. This is because I
want to push the speed dial number through the same sort of checking that
the sip phone's context does, without duplicating the logic.

Is there any way of gotoing a "context" (not a priority or extension) or is
there a  way of resetting the context so that execution starts at the start
of the context dialplan ?

Julian