Ah, that info is displayed via a 3rd party application (Airio?) - it can't (or any other 3rd party application for that matter) can't access your LFS license status. So it checks your LFSworld statistics - since you've never driven on S1/S2 cars/track online it thinks that you're a demo-licensed racer.
Nothing to worry about; as soon as you put down a few laps in S1/S2 cars/track online it should update itself. More to the point - Airio is a 3rd party In-Sim application which is used by most race servers and is nothing do with the LFS-developers themselves.
As for the cars being not available in S1/S2 hosts - server owners are using Airio to block out people with lesser online experience from driving in their servers. The online experience is calculated by the distance driven, races won, number of hotlaps uploaded and whole lot of more info as Airio's "LFS Experience Index". Example:
http://stats.airio.eu/EXD.aspx?U=victor
Try cargame.nl S1 server. I think you should be able to drive the XFG/XRG at minimum. As you start scoring points and gaining "LFS EI" you should be able to access more cars (FXO, RB4, LX4..) and so on. Eventually you'll have enough points/LFS EI to hop on to the cargame.nl server.
I pointed out cargame.nl servers since they're populated most of the time. Most of the other race servers don't have cars restricted based on LFSEI; just that they've selected a car/track combo for a specific time... Although I believe you would have a hard time finding populated servers in your time zone...