XeLaTex and Jurabib

Dear all,

I'm trying to work with XeLaTeX and Jurabib. Everything seems to work fine except for one odd niggle. I'm using Jox.bst and want article titles in single quotation marks followed by italicised journal titles. The opening quotation mark appears consistently as a ` character rather than as ‘ an opening quote. The closing quote mostly appears correctly but can be thrown out by, for instance, the last words of the article title being emphasised with \emph.  What to do?

I've had a look in the .bbl file but don't really know what I'm looking for. Where should I look in the Jurabib files to see how the opening quotation mark is specified?  Is this a Jurabib problem or an XeLaTeX one? Can one tell?

Any help appreciated.

Stuart