Howdy, Liviu!
Do you think that I lose points if I deliver the user documentation only as HTML ?
No. You have to choose one of the 3 ways to provide instructions to your users. This is the user guide, so if you provide instructions about how to use the application you developed, it should be ok. I chose to create only a plain text user guide, but the main point is to provide instructions about how to use your application in this document.
Cheers, Roberto Perillo
SCJP, SCWCD, SCJD, SCBCD