How to make a class partial in the R# SDK ?

Hi everyone,

I'm a brand new joiner in the R# plugin developer community, and as such my question might be a bit noobie :)

I need to write a plugin which makes the class I'm looking into implement a particular interface.
The glitch here is that I need to make this class partial, and to write the whole implementation code in the newly created partial class, to leave the existing class code as is.

I couldn't find my way through the plugin SDK to achieve such partial class change...

By any chance, would one of you know how to do that ?

Thanks in advance !

Regards

(and happy new year :))