Some Drum Plugins such as BF Drums do have a few default instruments which do not conform to the GM standard. You can reassign GM instrument numbers within BF Drums to play whichever instrument you wish and save a proforma setup for future use, but I am not familiar with JamSticks. However, there is another way - use Edit > Split Midi Drums which assigns a separate track for each drum instrument according to the GM Standard. You are now able to check what is played on any track and tweak the sound - Use the Classic Tracks Window and increase/decrease the number (default zero) in the column "KEY" using the +/- keys. This changes the actual note being played by one semi-tone at a time to play a different instrument.