[Therion] Centerline: missing start lrud values? How to compensate?

Hallo everyone, I have another little problem: I am entering LRUD data of my last mine survey, and I am missing LRUD values of the start of a centerline (way too besmirched paper;). Now, missing values in between would not be such big of a problem, but how do I compensate for missing start values? For now I have entered 0/0/0/0, but that does not seem to be a good way. Best regards, Christian PS. By the way: I have installed a debian within a virtual machine to temporarily solve that Loch compiling problem. But this is uncomfortable, of course.