My impression was that Axiom manufactured the drivers themselves rather than sourcing standard parts from VIFA or others. I could be wrong about the tweeters though.

Probably good first step would be to contact Axiom and see if they have any spares left.

Failing that the v4 tweeters would probably be as good a fit as anything else.

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