ok I tried it but can't get it to work here is what I got
(^<BuildNumber version=[[^<]]+/>)|(^<DataCenter name=[[^<]]+/>)
then replace with
(?1<BuildNumber version="3.0.0.0")(?2DataCenter name="ha ha")
by the way these are not the only things in the xml file the xml file containts many other lines and the lines above appear a few times under different tags paths...
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