How to find all controller:target ids used for RDM mapping on Virtual machine

I want to get a list of all target ids used for RDM mapping on each controller.  So next time I can use the remaining target ids for RDM disk mapping using perl script.

I have checked findVMsWithRDMs.pl but it is not showing target ids used for each RDM disk. I am using ESXi 5.5 servers and SDK for perl.

Thanks

AMrut