[XeTeX] Using math font packages with fontspec

[Dalyoung Jeong]

Hi, all

It is not the problem in XeLaTeX, but I think that my problem might  
be related with this post, so I'd like to ask about it.

When I use XeConTeXt, I defined a korean font as the main font. It  
worked fine in general.
However, the greek capital in math mode such as $\Delta, \Gamma, \Phi 
$ are appeared as the strange symbols. All the small greek letters in  
math mode are appeared well.

If I set the english font as the main font, there is no problem at all.
So I think that the large greek letters in math mode is replaced with  
strange symbols because of Korean font.

Is there a way to avoid such an replacement like in XeLaTeX( "[cm- 
defauls][]")?

Thank you.

regards,

Dalyoung