Custom characteristic to existing GATT primary service

Hi Dialog,

I had a confusion in creating custom services and characteristics. I can adverstise some data with my DA14695 USB kit. Once connected with my smart phone, I can see the GAP and GATT services. The server GATT has only the default primary service which is the generic attribute with UUID 0x1801 and also it says this is an empty service. Now my question is can I add my characteristic to this aleady existing dafault GATT service and change the UUID according to my service instead of 0x1801 or do I need to design a new custom service and the characteristics for it?

Thanks in advance.

Regards, Prasanna