remote over vnc.vnc over remote

[behamotul behemotilor]

hello.
pls some help
i want to get into a computer...and spy let s say someone who uses same computer through remote desktop
practically nobody uses the computer but remote...just someone uses remote desktop from windows and i want to see what he does
i tried but it did nt work with tight vnc,ultra vnc,and vnc 4_1..
what happened...it happened...that when i am using vnc end he enters with remote on same comp it throws me out.vice versa ..when he is remote and i want to spy him..it doesn t let me...
someone tried this?
i kind a need this version and not other versions of spying
thanks!