Can XPInstall do these things?

Hi.  I'm considering using XPInstall stubs as the basis for an installer 
for my cross platform desktop applications, not Netscape related.  I've 
read the prior posts in this newsgroup regarding this, browsed the docs 
and examples.  I have some specific questions about capabilities before 
I dive in.

1) Can XPInstall effectively install fonts on Windows, Mac & Linux 
platforms?  I'm accustomed to installers having specific "install font" 
functions, and I don't see one in the XPInstall API.

2) Can certain components be password protected?  I don't see any 
security/permisssion/access functions in the API.  If not, I'm thinking 
that I might be able to use .htaccess files on the server to handle 
this, but that would preclude using a distributable CD, at least for 
those components.  Anyone done something like this?

Thanks in advance

Rob