You can add an item there as a subtypte of the Custom Comp Colectio.
and Custom Component Template.
I do not remember at the moment - I would have to try to remind...but here is the library I have made 2 years ago as a "present" for Polish AC forum users. Analysing the macros can drive You to the way how to make Yourself a needed part/accessory
I can translate this object to English if Anyone is interested. However I hope the usage is quite clear, I enclose the manual also in Polish - I can translate it too.
The library contains the multipurpose objects for multiplication, free rotate - 2 ways and skew.
Best Regards,
Piotr