Hello,
To find your TestInstance ID, go login to MyPC (the web UI), from the upper menu click on Test Management and select Test Lab.
In the left part ofthe screen you will have the ability to filter by testset. choose the testset that includes your test, and then look for your test in the filtered list. for each row, you will see an ID - this is the TestInstance ID.
Hope it helps. let us know if you still have issues finding it.
Regards,
Oren Pelzman,
Performance Center R&D