When using custom VSM MQ steps, the VSE is processing transactions fine, but in the DevTest Console shows VSE Transaction Count as zero always.
DEVTEST versions 8.x , 9.x and 10.x affected
The reason you are not seeing transaction count in the model is that, a change was made sometime in the 8.x-9.x time frame that basically means VSE only counts transactions when the VSM-based steps are used. The code that increments the transaction count now looks for a special testExec property that those steps set.
If a VSM is not recorded one or uses deprecated IBM MQ publish /consume steps and if it has custom Java script steps you face this issue.
Here is something you can do to the existing model :
Include the following line in your script step just before the respond step and that should update the Transaction count.