asterisk users - Mar 2009 - Blind transfer from asterisk dialplan (and problems re-parking a call)

Hi,
Is there a way to do a blind transfer within an asterisk dialplan (like
'##')?
The reason I need this (I think) rather than a regular Goto() is that
I'm trying to do one-touch parking.
I can park a call using one-touch parking and then pick it up again,
however if I try to re-park the call, it gets lost.
I think that is because asterisk thinks I'm still on the park extension.

As an example:

exten => _9X,1,Set(PARKINGEXTEN=${EXTEN})
exten => _9X,n,Set(RETURNEXT=${CUT(BLINDTRANSFER||1):4})
exten => _9X,n,GotoIf($["x${RETURNEXT}" =
"x"]?usechannel:find)
exten => _9X,n(usechannel),Set(RETURNEXT=${CUT(CHANNEL||1):4})
exten =>
_9X,n(park),ParkAndAnnounce(pbx-transfer:PARKED|30|Local/parkannounce|ext-local,${RETURNEXT},1)

So here's what happens:

Someone calls in, the call is answered. A user speed dials using a
line key to extension 90, which parks the call on 90.
The BLF (linksys phones) lights up for that key, indicating the call is parked.
Going to another phone monitoring the 90 extension, you can unpark the
call by pressing the line key (which speeddials 90).
However, pressing that key again to re-park on 90 does not work, it
puts the phone on hold (because I think the phone thinks its on the
same extension).

Any ideas here?
Basically I have a customer that wants one-touch parking w/o having to
wait for an announcement.

Thanks.