Over the years I have made several modifications to the Text/HTML module in DNN.  I was wondering about packaging them up, putting some polish on them and selling them on Snowcovered.  I have the programming chops no problem but I am not sure if asking for money would put me in violation of DNN Licensing (have read About/Licensing which sounds like I can, but want to be sure).  I would guess about 80% of the code would be defacto out of the box Text/HTML.  I don't plan on making a compiled version, I would plan on making a duplicate definition, etc to avoid issues with upgrades to the core, etc.  So it wouldn't be difficult for somebody to take my source and do the same thing, which I don't really care about protecting but would like to make some money for my efforts (shareware type model).

My questions:

1.  Is this legitimate or would I have to release my version as freeware/BSD also.
2.  Would I have to retain the copyright statements in the source?  Would the DNN crew even want me to?
3.  If so would I just tack on my copyright statements around my source?

Not sure where to look for more information on this.  It isn't really being lazy, I have not problem with just coding my own 100% pure version also, I just want to be honest in doing it or not do it at all.

Thanks in advance.