Voxel replacement with CnCnet

[Weldie]

Hi all, first post, and probably a total noob question but;

I've been messing around replacing voxels for EXISTING units. (It's as simple as naming the .vxl and .hva files for the unit you want to replace, and dropping them in the main RA2 directory) I've been able to get this to work fine, IF I launch the game via the old gamemd.exe. 

However, if I launch the game via the CnCnet client, the edited voxels do not show up (the original voxels are used) Is this by design, (some sort of anticheat measure?) or, have I goofed up? Do I need to put my new voxels somewhere else?

Thanks in advance!