regular expression in XML Schema

Hi folks,

I am not a programmer of Java, perl or the like, but a data modeller and an XML
Schema designer from a modelling perspective.

The subject of regular expressions is puzzling me. I can read the XML Schema
Recommendation a hundred times and still not understand it, because there is not
a
single example given.

Two questions:

   *     Who can point me at some reference literature for dummies on this
     subject?
   *     or even more time-saving (because I really have one only problem to
     solve): who can help and wants to help me with the problem outlined below?

The problem is as follows: I have identifiers of the type Name, that must follow
the following pattern: AN__|AN__|identifier·an , where:

    AN__ = an alphanumerical prefix which is case-insensitive ending with a
double underscore; there may be one to many of such prefixes with no
    whitespaces in between
    identifier = an case-sensitive alphanumerical string, optionally including
the characters . and -
    · = the infamous "middle dot" (#x00B7) that is mentioned as an allowable
"extender" (if I understand the purpose of such "extenders" properly)
    an = a suffix that is an alphnumerical case-insensitive string

NOTE The latter two bullets are to be optional

EXAMPLES  XYZCO__HOU05__123b4X.1   and SHELL__LON87__40320-A3·Q4

How is the "pattern"? I now have
([a-zA-Z][a-zA-Z0-9]*__)|([a-zA-Z][a-zA-Z0-9]*__)| [a-zA-Z0-9.\-]+
(·[a-zA-Z0-9.\-]+), but that doesn't work and it
probably reveals my utter ignorance.

Please help!

Regards,
Hans

PS I am working on InfowebML, see our site.