Sorry for the delay Sebastian.
I see what you mean. Even if I did get the core working, I would not be able to use any 3rd party modules without having the source code and updating them.
Looks like I am going to have to abandon DNN, at least until there is a possibility of using other databases e.g. if the core team decide to use Entity frameworks or at least an ORM.
I have invested a lot of time into it. 
I think that any support of multiple databases must come from the core team as a means to drive 3rd party developers.