Can I say my Dhamma is Kamma?
I pay homage to the Buddha, my Karma and the Sangha.  

I pay homage to the Buddha, the Karma and the Sangha.

I don't know...

I never heard anyone refer to the Dhamma as a possession or something that is spoken of  dualistically  like karma (my good dhamma, my bad dhamma). So just grammatically it doesn't really fit.

Really, these are just words. Ultimately we don't possess anything and there is more to the Dharma than just karma.

On the other hand, concepts in Buddhism fit together with such incredible grace that it can sort of seem like one concept is the same as the next concept but from another perspective or in another context.

I hope I'm not misunderstanding your question and I hope this helps.-metta