[mythtv] where to add pdc/vps funcionality?

[maestro]

hi all,

i don't plan to give up on this but it seems as if i'm at the end of my
knowledge, so i come here and ask for your advice.

some might know that i'm working on pdc/vps integration into mythtv,
since receiving vps signal is no problem with newer ivtv drivers my
question is, where that code would be best added.

as far as i know a suitable EncoderLink's StartRecording function is
called by the scheduler when it's the time for a show do be recorded.
(right?).
that (possibly wrong) assumption made me add the vps check code to
EncoderLink::StartRecording with the result that the backend blocks
until the correct vps signal is received (which can take a very long
time)
it was something like 
while (!CheckVpsStart()) {sleep(10);}

so my resulting questions are:
1.) where can i add the code that it will not block anything while its
still waiting on the correct vps signal. 
2.) should i do this on another way then the above mentioned, and if so
how?
3.) when startrecording works where would be the correct place to check
for the stoprecording vps signal?

i've asked a similar question 2 or 3 weeks ago but didn't get any
answer. if there is something wrong about my mails, the kind i'm asking
questions, the tone i'm addressing you please let me know so that i can
work on it. (i'm not a native english speaker so please be patient)

so long & hoping for some answer
maestro