Create and customize a Voip SIP client for Windows

I want to build a customized SIP/VoIP Softphone with one new Skin design as per choice and my logo for unlimited user license that runs on PCs. Windows. The server side it's done and use Asterisk server with PJSIP. I would like that the developer use other solutions to do that, doesn't start by the zero. I hope at least these features in the 1st step of the project: - make and receive calls and video calls; - have a contact list to make calls and if possible access outlook contact list; - register the calls realized in the history; - make conference (add member in a existing call); - send SMS and internal messages for your company user (plus);