asterisk users - Jan 2009 - G729 VAD issue

Hi,

My setup is SIP Call-->Asterisk-->VSP1 or VSP2 or VSP3
I'm experiencing an interconnect issue with one of the VSP's that seems
to
have to do with Asterisk not having any VAD control. The error is:

NOTICE[10989]: frame.c:203 __ast_smoother_feed: Dropping extra frame of 
G.729 since we already have a VAD frame at the end

The VSP has switched off silence suppression on their Quitnum device.

Any ideas are most welcome.

Thanks

Shaun