BnSBuddy doesn't support bnspatch's .xml files.
You have to rewrite your own addons manually.
To use addons in bnsbuddy, just install the plugin loader and then install the sigbypass plugin.
This is all done in the extras page.
To use bnspatch, just click in "bnspatch" in the addons page.
Rverything is explained on the "help" button of each window.