thanks also for the suggestion. I haven't tried Omnis yet. The website suggests that W300 is one of the few handsets unsupported for code reset Phone info | Omnius
I'll give it a try nevertheless.
:( no luck
it seems this phone is cursed and I am doomed to have a Walkman that looks like a phone.
The upside of all this is I now consider myself a Sunday expert at unlocking old Sony Ericsson mobile phones.
Any other suggestions would be greatly appreciated.