Thanks alot, Ian and Frank
(Frank and Ian)!
your help and sharing your exp save me a lot of time and trouble 
1)
I read that:
 - DNN4 uses WST
- WST and WAP project cannot be mixed - either one or another but not both
Does this mean that I cannot use WAP having my custom module development inside the DNN4 structure?

2)
One of my task was to get  3d parties module and modify it.
The Private Assemblies variant of module works and has a lot of dll telling me that it was developed with WST type of project.
But source variant module is not installable. 
The author of the module responded something irrelevant to my question on it

I'd like to understand:
? Is it possible to have problems if the module was developed in one of the possible configurations and I am trying to use another
In my case, I used File-based DNN04.05.05 (installed through StarterKit installation) project and I guess the module was possibly developed under IIS variant of DNN4.05.05 (but I do not know)?
What are your advices for configuration ofDNN and development environment in case of re-development of 3d party modules?

Thanks once more for your participation!

Guennadi Vanine - Gennady Vanin - Геннадий Ванин 
BTW
I do not receive Email notifications. Why?