[XeTeX] Underline thickness and position for Type1

[Pander]

I think several real world applications of underline exist, also in
mathematical environments, you can use it to indicate specific
characteristics.

So to come back to the original question. I think, when a type designer
has taken the effort into specifying underline position and thicknes
(wheter you use it correctly or not, you can also abuse quotations for
stress) XeTeX should be able to use these settings.

In short, this is a bug which should be fixed?