You can override the default dataset name for these transaction dumps. In your HLQ.SAMPLIB(MSMLIB), this is referenced on the STDENV DD statement in the MSMTC startup procedure, at the end of this member you should see export IBM_JAVA_ZOS_TDUMP.
You change it to:
and also code:
export JAVA_DUMP_TDUMP_PATTERN="HLQ.DUMP" where HLQ.DUMP is the high level qualifier for the transaction dump dataset.