Depending upon how much concealment you actually need, in the darkness, you may be able to find what you need in the Safariland system, if Safariland makes a WML-compatible holster body for your pistol/WML combo. I seem to recall a shoulder rig, for an ALS and/or SLS belt holster body. The Safariland maze is difficult to navigate, but there are so very many combinations.
Some customs makers, also, make various things combatible with the Safariland bold hole pattern.