Hi ,
Please use the assign transport request option on transport management -> More to map manually created TR's in ChaRM, but it will allow to map TOC. if you have any TOC and try to map in ChaRM, then create the new transport in ChaRM and copy the changes.
Please check the below demo for more details.
https://websmp108.sap-ag.de/~sapidb/011000358700000611352012E/index.htm
Rg,
Karthik