integer user names and user quotas!

hello,
i want to implements user quotas. the problem is that all of our user names are integer numbers, like 8510453.

so when i set quota for a user (e.g. 8510453), it wont be set for that user name instead it will be set for exactly this: #8510453 (this is what webmin report shows).

i have tried both the edquota command and webmin module but no differences.

using a string user name (e.g. mrhosseini) will works correctly.
any idea? (we can not add any other character to user names.)

our server is CentOS 5.02

I'd suggest looking up the necessary UID's and using those instead.

unfortunately UID's are the same

Can you check with an actual console to verify that the uid's are not being properly set?

oh! sorry! I was incorrect. UID's are different. But the problem is that now we just have the user names not UID's (because we store users info in a ldap server). how can we get UID's from user names in a client?