Call parking in one step

hello all…
i ve read like to park a call in asterisk i need to set
parkcall => ** in featuresmap context of features.conf
however the keys can be anything…
this can park the call in one step…
but along with parking…i need to retrieve the parkingslot number for further use…
how can these things be achieved?

or put simply
i want to call A
then put him on hold and connect to C
then end the call with C and come back to A
can anyboly help me out??

I have responed to this post on the asterisk support forum