If you are looking to monitor Tivoli Framework from ITM, the best way is to develop an Universal agent or agent builder to pull framework metrics using your custom script. Needless to say, Framework provides a vast array of commands that can easily be scripted to get you the metrics you needed.
If you are looking to monitor basic server components such as TMR, ManagedNode, epmgr and gateways and if you are at Framework 4.3.1 or later, you are in luck. You don't even need to develop an MDL. Framework 4.3.1 provides a new component called tmfmon that provides necessary MDLs and commands that can be readily imported into Universal agent.
You need to take a look at $BINDIR/../generic/tmfmon/README file on how to implement this solution.