i don't understand why you don't just use a combobox to find your customers. it would have similar code to CyberLynx, but the combo would allow your user to pcik from a list of customers by name, and the user would be able to see all available, rather than having to guess which customer has what autonumber, let's not even mention if a customer doesn't already exist!
the combo would use your customer table as the source, and then you'd clone the recordset blah blah to fin the record. SOOOOOO much easier... and seems to be the method which attracts most information on these forums - so there's plenty of info about it already here.
if you really want to use the filter option, have a look here for an example:
http://allenbrowne.com/ser-28.html