Sonar 8.5 Sync Issue

Hi everyone,
 
I've never encountered a problem with sonar before, but since setting up the studio again, nothing is going right.
 
I'm pointing a microphone at my PA, and hitting record on sonar, with Sonars audio metronome going. When I playback, listening to the metronome I recorded and sonars playback metronome they are very much out of sync, and keep getting further and further out of sync the longer I record.
 
I'm running Windows XP, 4GB ram, Quad Core 2.8ghz processor and running Sonar on WDM/KS drivers. For the audio interface I'm using a Presonus Firestudio, this is bypassing the computers internal sound card.
 
I can get Sonar to record the metronome in time if I switch to ASIO drivers and bump up the "Record Latency Adjustment - Manual Offset" to about 100. However, I'm trying to also sync a second device (Zoom H4n) and with ASIO drivers I can't get two devices to record at the same time. Though on another note this shows that ASIO will record it all at the same time whereas the WDM will get further and further out.
 
Any help will be greatly appreciated,
Kaine

Thanks for your fast response.
 
Sorry, I should have clarified further, we want to use the ZOOM not for it's inputs, but rather for it's XY stereo mic config. However, we don't want to plug it in solely as a mic into the interface as we'd prefer to keep those channels free for other things.
 
Even if I can't get them to work together that would be ok, it's not a huge deal, just something we wanted to do. However, if I unplug the ZOOM completely, and just use the firestudio with WDM drivers it still suffers the exact same problem with sync. Any ideas on that?
 
Thank you,
Kaine