Samsung Galaxy S :: Phone Not Correctly Switch Back To 3G After WiFi Connectivity

Very happy with the i9000 in the last few days of ownership, using launcher pro in place of stock but otherwise mostly unchanged. One issue we have is that after being at home overnight on WiFi, the phone doesn't automatically re enable 3g. To restore the mobile data you have to go into the network operator selection and re select Optus (our carrier here in Aus). Leaving it on auto doesn't help, and you have to manually choose it each time (ie: it "forgets" what I selected or something). Using apndroid to mangle the apn on/off doesn't help. Restarting the phone fixes it but obviously not ideal.

Have tried entering the code to change it to gsm only instead of the default wcdma/gsm auto with no benefit. When the mobile data is working, it happily switches between 2g and 3g, but will sometimes simply stop working as per the wifi overnight problem and I have to manually select the operator again. This happens very randomly and can go several days without drama, our only a few minutes. While this data won't connect, the phone capabilities aren't affected and you can make and receive calls fine. In fact if you dial a number it sometimes causes the data to re connect.