slides (FoilTeX) missing?

[Emanuele Olivetti]

I'm trying to make some slides as I did 6 months ago, but now on my latest
LyX release (1.1.4fix3) I can't find slides(FoilTeX) document class...?
Why?

Previously I used LyX 1.04 and everything works well.
How can I add that document class now (without upgrading)?

Thanks in advance.

                                        Emanuele