The VoiceLive products are really designed to be used with a single microphone plugged straight into it and not to be used in a loop type configuration. If you do want to use it in a loop, you will need multiple DI boxes to accommodate the input and output signals.
Take the aux send from the mixer and plug it into a DI box to plug into the VoiceLive XLR input. The output(s) should be returned onto a mic channel(s) if at all possible. If this is not an option you'll want to use a passive DI box in reverse. Take the output from the VoiceLive into a DI box XLR output connector. Keep in mind you'll also need an XLR female to female cables to accommodate this connection. Take the 1/4" input on the DI box and plug it into your returns of your mixer.
Using this method, the signal returned from the VoiceLive play will be layered over your dry signal. In the case of effects like Reverb, uMod(Micromod) and Delay, this may be exactly what you're looking for. If that's not the case you may want to turn on the 'lead mute' under setup.
When using the VoiceLive play in a loop, you will need to turn off harmony, double and hartune effects as these effects are not designed to work in a loop with multiple voices or microphones. If you are using these effects with one microphone/signal only in the loop, you may want only the effected signal to be returned. The effect would then operate as more of an Insert. In order to accomplish this, set your Aux send to PRE-Fader and then turn the volume of your channel fader to 0.