A word of warning!!!!!
My JTAGICE-MKII has been supplied with a JTAG PROBE which does not match the documentation. I assembled some PCBs today with an ATtiny45-20MU on teh board, there is no ISP connector, we use an 8 pin IC test clip to connect to the chip to programme it.
Following the pin-out listing and colour code given at the very end of the "Connecting to the target through the JTAG interface" I found that AVR Studio 4 always showed the Vtg to be 1.9V (I actually measured it at the device as 3.3V) and I am unable to read or set fuses.
It turns out that the JTAG PROBE board has the 10 pin female straight connector mounted the wrong way around. The indexing key faces the FPC connector, not the green connector as is shown in photographs in the documentation. Interestingly, my probe board has no silk screen legend on it either, so I have marked some pin numbers on it based on the photographs in the documentation.
Nice one Mr Atmel! About 6 hours lost chasing around to find your quality control error, and possibly as many as 6 ATtiny45's looking more than a little sick right now. I can only hope the ICE is not blown up, otherwise I will be even more mightily p****d off.