bar coding and portable devices

this is a generic question not tied to BPCS or any specific portable
data entry device.

our current practice is to print work order forms, send them to the
stockroom to be pulled, they write the actual qty pulled and from what
location, then they forward one copy of the form to a data entry person
who sits and enters the transaction into INV500. i'd like to give the
stockroom staff a portable data entry terminal and have them enter the
transaction themselves. but i am running into interference from some
parties who say that if i did this there would be no audit trail or
verification of the transactions and quantities that were actually
entered. 

so my question is: how do companies audit the various transactions that
are made using portable devices? how do you know that the proper
transactions are being made? how do you prove it to the accounting staff
and their legions of auditors that want to see source documents and
transaction audit trails?

chick doe
prime measurement systems