How to add subtemplate


recently we used to include sub-templates (saved in folder /subtemplates) in our custom templates created for Doc. Composer.
Question is: How to add / edit sub-template in Visual Paradigm 12.2?

It seems that VP properly import previously created templates to repository, but it is impossible to edit sub-templates or add any new.
It was important feature for us, allowing to build recurrent templates for example.

Looking forward for answer.

Paweł Kurek