detection rules in web_browsers_patch.xml

[mimmi]

I want to detect the newsest Opera Browsers with its correct version.

e.g. the user agent for an Opera 11.5
Opera/9.80 (Macintosh; Intel Mac OS X 10.7.0; U; de) Presto/2.9.168 Version/11.50

This Browser is detected as Opera 9.

How must the detection rule be to get the right version? The rules I found (in the files wurfl.xml and web_browsers_patch.xml inside the attribute "user_agent") dont look like it is possible to define a rule as an regex.