IMMIHELP. pls help. advise needed

[sprk]

This case is 3 years old.
my mom travelled to u.s on a multiple entry visa in 2001. she got a 6 month stamp at poe. we applied for a 1 month extension . she got the receipt from INS for the same. she left the country 13 days after the expiry of her old I94. after she left, we got the approval of her extension too. Unfortunatly, this original approval letter is now lost.
She wants to travel to the u.s again end of june.
Can you guide me if
1. Can she safely make this travel with just the receipt from INS
2. I am going to apply for her duplicate approval. does anybody have any experience with duplicate approvals? does INS keep records well. do you know if we have a good chance of getting it?
3. other than duplicate approval, will i need to get anything else?

please respond. v stressed.

Thanks

[srikar]

FYI only
Just wanted to share this with you.

http://www.msnbc.msn.com/id/7829682/

[sprk]

yes, i know about this story...hence the stress.
the difference between their case and my mothers is, she got a confirmed approval. has a original receipt of application and left within a 13 days of old i94 expiry and 5 days of receipt arrival.
i have already decided to apply for approval duplicate. i only wanted to know if anyone has any experience on applying for duplicates and if uscis keeps documentation well.
soumy