May be this will be helpfull for somebody,
Our original problem is that the following filter did not work for us
because case sensitivity
iif(COUNT(
FILTER([Users].[User].MEMBERS, USERS.CURRENTMEMBER.NAME = USERNAME)
)=0

we found that this will deal with will make the filter case insenistive
using intersection
"select intersect(
FILTER([Security USERS].MEMBERS, [Security USERS].CURRENTMEMBER.NAME
<username+"!"),
FILTER([Security USERS].MEMBERS, [Security USERS].CURRENTMEMBER.NAME
scearios..

I'd love to get feed back from people hwo deployed 64bits specially on the
topic "is MDX sustainable without VBA"
Also an official list of VBA functions integrated into MDX in SP4 will be
very handy.

Thanks
Nabil Majoul