XSLT Regex for Matching Curly Braces

Hello,
I'm attempting to write a regex inB  XSLT on matching curly braces and then
produce the correct markup output. Between my lack of expertise in regex
generally and the special circumstances in XSLT with regard to AVTs and curly
braces I'm having little success.
The requirement is pretty straight-forward. Given a text node such as this:
}B dui {elementum}.B Potenti ullamcorper vitae tempus condimentum dignissim
facilisis arcu ligula {elementum} {
I want the output markup to be:
}B dui <ph>elementum</ph>.B Potenti ullamcorper vitae tempus condimentum
dignissim facilisis arcu ligula <ph>elementum</ph> {
So, two parts to my question:
1. What is the correct regex in XSLT to match a set of curly braces with one
or characters between them and no white space?
2. Is <xsl:analyze-string> the best choice for processing the string via the
regex and handling the output or is another approach preferred?
Thanks
Don