I did the test and it works but only in bridge mode.
I could establish ospf through the CSM between 2 routers configured for mpls.
OSPF comes up - so multicast can go through the csm.
I could form TDP adjecency and learn all the tags.
Then I sent some traffic in mpls and it went through the csm.
The CSM does not understand the mpls traffic, it is just passing it through like a L2 switch.
Again, this requires the use of bridge mode.
This does not work in routing/secure mode.
Regards.
Gilles.