[XeTeX] How to use EC font encoding in XeTeX?

[Mojca Miklavec]

Hello,

XeTeX supports the "old" was of selecting Type1 fonts, but how can I
trick it to use "čšž" (ccaron, scaron, zcaron) when typesetting in
that font? (Yes, I know that using OpenType is the preferred way of
selecting fonts, but I first have to find a way to preload all the
dozens of OpenType LM fonts by default and there are some fonts which
I don't have in OpenType format anyway.)

Thank you very much,
    Mojca