Bouncing And Asio, problems bouncing using ASIO Options

[willm]

Hello all
My problem is that when I work with ASIO I can't bounce down to a stereo file. With Mac AV it's not a problem. When I hit bounce in the environment window I get the following message: 'Mac AV is not available'.
If I switch to Mac AV then I lose all my plug-ins. I'm using OS9.2, Logic 4.8.1 and a Waveterminal U2A USB interface (humble, but who cares?). I'm working with audio only - no midi. (I realise that the OS9 forum might be the place for this query but it's no doubt of such a basic nature that 'getting started' seemed a better place for it.)
Thanks for listening.
Will M