I've noticed that in Transmission 2.61, I'm not be able to set or change any speed limits through the Web interface.
I have a laptop with a AZERTY keyboard layout without dedicated keypad.
I can type the "normal" character assigned to the key but not the number that come by holding the Shift key down.
The workaround that works : basically copy paste the value in the fields
On my system, numbers are usually typed by holding the Shift key.
System : Xubuntu 12.04 LTS 64 bits