GUI - to much email users

[egidux77]

I'm stuck with problem of managing email users. Have about 2000 mail users per domain, and when i want to change pass or something else get internal error 500. Is there is some ability to set mail users per page in administration page? I'm searching this forum for hours, but didn't found anything similar. And it is big problem for me, now I can't administrate email users.

Using:
ispCP 1.0.5 OMEGA
build: 20100331
Codename: Priamo
CentOS 5.4.