cv.jit tracking

hi,
i've been studying the cv.jit library and specificaly the
cv.jit.blobs.centroid object, and it seems that it does the tracking that i need. my rpoblem is that i can't get out the x,y positions and area data for more than one blob at a time. using
the jit.unpack object i obtain this information only for the biggest object detected. i do it by putting a 3 argument for the unpack object. but if i put 6 or 9 or whatever it doesnt gives me anything else. do any of you have any idea of how to take out this information of the cv.jit.blob.centroid. because in the draw screen i actually see that it does the tracking for all the objects detected.
thanks in advace!
r.