All icon number in shell32.dll don't work for changing icon of HDD

[spdCHF]

Dear fellows , assuming that you know how to change HDD icons ,I ask why an icon index number greater than 48 in shell32.dll is not working . Is there any limitation ?
For clarity I say that I am using windows xp sp2 and the method I am using is the autorun program :
[autorun]
icon=c:\windows\system32\shell32.dll,52 saving as "c:\autorun.inf".
With regards, spdCHF.

[Salmon Trout]

You did know they stop at 49 and start again at 54?

Could it be to do with that?

[spdCHF]

Thanks for response ! Yes sir, I used the numbers and tried several such numbers in vain ! If you know any other syntax for the 'autorun' program help me .

[BC_Programmer]

try using a negative value. This worked for me.