I haven't used the converter but I know someone who has with a via 6421a pcmcia card (pluscom), it flashed a liteon in windows no problem using UniATA driver, it was £30 delivered from Hong Kong, he says all his pcmcia cards work perfectly in the converter, even a 56k dial up pcmcia fax/modem.
I haven't come across any posts where users say they have tried a converter and failed, but, even with a Via 6421 card, wether using the converter or not flashing straight off is normally not possible using the via drivers, this is maybe why you heard flashing does not work with a converter, the via drivers poll the attached drives, once the drives are erased and in vendor mode they normally freeze your laptop, and you can't drop down to dos, even with cardservices for dos installed your pcmcia card will not be available, that's where the UniATA drivers come in, they do not poll the attached drives and allow flashing with a via card without any freeze.
Liteon drives can be especially problematic, but all drives can freeze with via drivers, here is a quote from the thread I posted the link to in my first reply to you, concerning the UniATA drivers:-
Quote : Had a samsung drive that was so problematic it would freeze my pc in dos. Had never encountered anything like it. In windows I could not get past vendor intro. Decided to try this out, loaded the drive up in windows on the first try! Unbelievable, I was finally able to pull the keys from it. /Quote
Concerning the ICH7M chipset, I don't know why it failed to flash, I have not used this chipset to flash a drive, but there are things you can try, like changing install strings for the chipset to report as a standard ICH7, you can even change vendor ids in the install ini file to install a different driver, there are normally always work arounds. I can't confirm anything definite about this particular chipset, but mobile chipsets normally have the same capability as desktop, they are just designed to be more conservative with power usage.
I think if you made a winxp live disk with necessary tools and played around with driver installs for the ICH7M it should flash if other ICH7 are capable.