Hi there,
 
so I was trying something different. Instead of just sticking to the Drum Banks (or "programs", ".prog"-files as they are called...) that already exist in a vst-plugin (e.g. the "SI-Drum Kit") I wanted to use my own sounds to make a drum loop.
 
What I exactly had in mind was this:
     1. record some short sound-samples with my microfone (e.g. click with tongue, finger's snip and clap).
     2. get this little bunch of three sound-samples into a bank and save it into the "sound-store" of the vst, (so the place where all audio and sound-samples are kept)
     3. IF NECESSARY (and that's crucial): create a .prog file and assign each sound-sample to one particular midi-note, so that I can use my sounds to make some kind of a drum beat, (just as I'd be using the drumkits that the vst offers).
 
I hope somebody was able to follow me to help me out of this.
Best and thx in advace, WhiteSheet.

Its pretty simple using Session Drummer.
 
First record your samples in Sonar and export them to separate WAV files
Insert Session Drummer into your project
In the Session Drummer interface click on a drum, then click on the box next to Drum -> and select one of the WAV files you created. 
Repeat for each drum you want to change.