Idiots guide to connecting palm T3 and SE Z600

I'm getting very confused. I'm trying to compose and send texts from my palm
T3 via my sony ericsson Z600.

I have managed to download texts received on the phone to the palm using the
SMS application but couldn't send one.
Today I can't do either. I'm getting a 'phone error' 'unable to connect to
phone'.
I tried deleting and remaking the connection between the two.
The palm is set to discoverable and connectable.

Some facts and helpful notes:
Neither SE or Palm have a driver for the z600.
I found and installed a 3rd party z600 driver (on the palm gear website I
think). Initially it didn't seen to work but has since appeared on my palm
as a z600 driver!
I had to delete the sms application with Filez to get it to run. Basically,
I synced everything across from my old palm Tungsten T including the sms
application but it must have clashed with the new one resident in the T3's
OS. It only showed as one icon so I had no idea I was trying to use two of
them.
Although the z600 driver appears in a device list on my T3, it still doesn't
appear in the 'make new connection' wizard on the T3 - probably because
it's 3rd party.
I can send pictures between both devices in either direction.

Can anyone help me make sense of what I might be doing wrong?
News of a genuine z600 driver might be a good place to start but an idiots
guide to setting the damned things up would be great.
yours frustratedly
jc
ps it sort of goes without saying that the palm and SE support is not very
good so please don't send me back to them!