Hi!
I have Sonar x1 LE and I cant get the SI drumkit to work. When I insert it as a soft synth I get sound from the drums but as soon as I connect it to a MIDI track the sound disappears. I have chosen the SI drumkit as output on the MIDI track and as an input in the Audio track. I can get the other soft synths to work doing the same thing but the drumkit simply wont work.
s there any friendly soul out there who can help me with this problem?

Have you tried a 'simple instrument' track (drag from browser) ... or do you specifically want to separate the audio and MIDI tracks?
(Either should work though - can't think where your issue is ATM).

Does the track play in TTS-1?

Try this, making sure SI Drums do work in the first place.
 
1. insert SI Drums as "simple instrument track" as suggested by ShellstaX.
2. load up any drum kit sound.
3. click on step-sequencer and program a simple pattern
 
If it does have sound, then we can be sure it's not an issue and can inspect other issues (the midi track that you pull in may have notes that is outside of the SI Drums range for example).

Yeah - previous entries are heading down the 'ensuring your source midi is mapped properly' route.
 
Another potential 'simple' possibility is that you have not loaded a 'program'. But then again SI Drums typically has default.prog loaded ... and you say you are getting sound 'interactively'(?).
 
It could also be:
- input / output routing (simple instrument should sort that out).
- audio issues (buffering etc).
(although perhaps less likely as your success with other instruments suggests you may be OK there).

Thanks for your help but I still cant get it to work.
When I insert SI Drums as a simple instrument track I do get sound from the drums when clicking on the drums or picking a beat. But when I then insert my MIDI track in the simple instrument track and plays it there is no sound. And when I open up the SI drums again I get no sound from it when I´m clicking on the drums or on the step sequencer. So just by inserting my MIDI track the sound disappears. If I deletes my MIDI track from the simple instrument track the sound is still gone. I have to delete the simple instrument track and the SI drum and insert both all over again to get the sound back.
And as I said it all works fine with every other soft synths, my MIDI track plays well with MT-PowerDrumkit for example.
Thanks for your time.

The problem is most likely data in the MIDI track. The is common for MIDI clips created outside of SONAR and played through Cakewalk sfz engine synths. Usually it is at the very beginning of the MIDI clip. Either open the MIDI clip in the Event List and remove the data up to the first note and/or BEFORE playing the MIDI clip select "Do not intercept NRPNs" in the VST Plug-in Properties page from the VST drop down in the standard header for the SI-Drums UI.

You my friend are a genius! Now its working fine.
Thank you very much!

What's the source of the MIDI? If scook's suggestion doesn't work and it's not against licencing post it somewhere and we'll take a look. 
 
[ignore - resolved - good stuff ... actually no - what's the source so we aware of potential issues with that vendor?]

I´ve created it in Guitar Pro (5) and just exported it as a MIDI file.