Stereo Output Problem

Hi, I am having a problem with my stereo output in X3e.
My audio settings are: M-Audio USB ASIO (Analog 1/2 Fast Track Pro output. Now here's my problem; I convert a mono track to stereo and insert the Sony multi-Tap plug-in (which simply offsets the two tracks for a pseudo stereo effect). I don't recall this in previous versions of Sonar. The track icon indicates the change from mono stereo but it's still only outputting a mono signal. The problem is, I'm now getting the usual phasing that you get when you have two tracks the same and the output has no stereo separation at all. The pan control does work as it should. Output is set to 'Master' and interleave is stereo.
 
 If I output the same mono track to Soundforge (which uses the same audio interface and output settings) and apply the same stereo split and Sony effect, the result sounds as it should; panned hard left and hard right. When I bring it back to Sonar I get the mono sounding track with the wave phasing. This seems to indicate to me that it's a setting within Sonar and not the audio interface. This was not a problem with 8.5. Any ideas guys?
Pete.