[Asterisk-Users] SIP re-invite and billing

[Mojo Jojo]

I know this may sound like a stupid question but I will put on my flame 
retardant suit and ask anyway.

Is there any way to use/allow SIP reinvite and still track the length of the 
call?

I realize that the whole idea of reinvite is that it takes the proxy out of 
the media path which, from what I understand also kills the proxy's ability 
to track the start/end time of the call for billing purposes.

Are there any really smart guys out there with propeller hats that have come 
up with a way to get the best of both worlds?

Do we lose anything else using reinvite with Asterisk?

Thanks in advance for any help..

--Mojo