This looks like a bug we need to fix. For now a mystical incantation should make the magic work! In Header+Footer, you have the Center header as "Page Number" from the drop down list. But you can actually type into those entries. You need to replace the text that is there with: \cstyle{hR}{\pagenumberR}
This says to make the Center running header be the \pagenumber from the right hand column and to style it using the \h of the right hand column. It's that latter bit that will enable it to come out in Latin.
Or... just wait for the next release of ptxprint, which like buses, come along pretty regularly. And if this is urgent, call out and we'll get a bus on the way.