Change equation, the fonts

[Pep Roca]

Hi:

In my documents I use avant font (I have in the preamble 
"\renewcommand\familydefault{\sfdefault}"). But in the equation, the fonts 
are, not avant. There are any easy way to configure that in all the equations 
LyX use avant fonts, instead times fonts? Thanks in advance.

Thank you very much again, to all the LyX developers, I think that is a great 
program!!

Regards. P Roca