>>You mean flush-mounting them in the ceiling (says Mojo as he makes a cross with his two index fingers) ?

Yep. I don't think the holders are designed to work that way so it would take a call to Axiom to confirm it can be done.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8