Pb installing windows agent, not enought space on c drive

hi,

i have this problem since V10, to install the windows agent, it requires 1.5Go on c driver. On some server, i cannot have this space. Even if we ask to install on d:, it still ask for this amount of space on c:
I downloaded the last release hoping this problem would be fixed but still not.
Can somebody help me on this and please, do not tell me to free spaces on c driver, i can't.