character escaping

Hi,

I got another question. 

It's about character escaping in the regex function. There seem to be
two ways for this.

\\x00 for one character which is ASCII and \u0000 for a unicode
codepoint. This goes fine. I tried \\x{..} as well but doesn't seem to
work in my environment. My problem is that I get escaped characters
which have a longer hexcode in chunks of two, i.e.  u + Umlaut U+00FC /
C3BC as "\C3\BC". If you have only characters like that in a foreign
script you get a whole line like this and it is a problem on how to know
which is which. So I was wondering if it is somehow possible to simply
transfer this to \\xc3\\xbc.. in a regular expression without having to
use unicode codepoints.

Thanks again

Denis