I just did a bit of Googleing and found this thread

Lifted from the thread:

Actually you aren't seeing the exposure meter in Av, Tv and P modes... You are seeing the Exposure Compensation display.

There's no use of Exposure Compensation in M mode, so it's blanked out in EOS Utility.

So in other words you really don't see the exposure meter remotely in any mode. You only see Exposure Compensation in modes that can use it.

These is no real use for the exposure compensation display in manual mode via the EOS utility. The cam decides the relevant aspect(aperture / shutter speed) to change in TV and AV modes - where as in full manual mode the utility is probably expecting you to alter this based on say a light reading / or other method to decide exposure.

If you were to use this exposure compensation display in full manual mode you would have to interpret how to adjust the shutter or aperture yourself according to the bar - not as accurate as other means. It would be far easier to take a shot with AV / TV mode, note the settings and move to manual mode or as suggested in the thread you could use live view / histogram to check for correct exposure.

Another suggestion would be to use a light meter to get the correct exposure for your shot.