I'm just putting a new server together and i also have the problem that the storage monitor doesn't give any redstone signal. in the last 2 days i ran into some other problems and experimented with some different rp2 alternatives and here's what i found:
vanilla redstone - no signal
ProjectRedBase-1.6.4-22.214.171.124 - no signal
EnderIO-1.6.4-0.5.5.136 - no signal
redlogic-57.2.6 - works fine with red alloy wire
Scince the monitor shows the correct eu amount in my mfsu i don't think it's an ic2 exp problem but has something to do with redstone. The monitor has an issue with energy cubes from mekkanism, but it's only a minor one. It shows the stored 2 MJ of the basic cube as 200.000 but works fine.
Hope the signal problem can be fixed, because i plan to stay with projectred and don't feel like also putting redlogic into my server only to be able to use the storage monitors.
edit: forgot my ic2 and gregtech versions: