Some SCSI cards too fast for UMAX scanners?

We have previously covered success and failure using UMAX scanners connected to SCSI cards in G3/BW Macs. SCSI bus and SCSI ID number issues were discussed. Here's another wrinkle: Keith Peregrine was using a UMAX Astra 1200S scanner connected to an Adaptec PowerDomain 2940U2W card. he had the common problem of the scanner not being recognized by the software. UMAX tech support told him that:

"UMAX scanners will not work with the 2940U2W card. The reason they gave was the card processed the throughput data faster than the scanner could handle it. There was no fix and UMAX was not going to update their scanners to work with the faster SCSI cards. Their only suggestion was to use one of Adaptec's slower cards."

Update: Thomas Ferrell writes: "A workaround is to temporarily connect a non-U2W hard disk to the U2W card. All devices on the chain will then slow down to the substitute drive's throughput rate."