How do i allow other user roles to edit/add fields in custompress

Hi using custompress. I have additional roles, based on administrator role which i give to the client. I need the client to be able to add/edit/remove custom fields using custompress but not able to have custom press display in their login, and wondered how this could be done to allow them to see and be able to modify the custom fields.

I have checked capabilities and there is nothing there that relates directly to custompress.

Many thanks and look forward to your answers