OpeNni: Color coordinates to depth coordinates

Question

I was wondering how can I convert a coordinate that i acquired from a full res color image to coordinates in the depth stream.

E.g, i got (763,234) from the full res color and i want to know what is the (x,y,z) from the depth image ? (btw i'm doing this in java, but an answer in c++ is probably easily translatable)

Thx in advance