No.

You have to either place your MODX Performances on Soundmondo using your MODX then you can sync your Montage to receive these Performances (one-by-one) or you buy software like JM Tools that I'm assuming can translate between X8U and X7U. Check that assumption with documentation and/or JM support and/or someone else that has these tools and used it for this.

Hi, John Melas Waveform Editor allow copying MODX file data into Montage file format and vice versa :

http://www.jmelas.gr/montage/wave.php

John Melas Tools thru performance editor allow to load Montage Connect and MODX connect file, so it can work if your performances are not using samples/Waveforms.