Hey I just got the X10 Mini Pro a few days ago. I updated to 2.1 right from start. I am having the same sms issue. I try to set the sms center in the network settings but no luck I also tried dialing *#*#4636#*#*, I get to a system menu where the options to set SMS center number also exists but I still can not set the SMS center number.
This is the number I've been using: +13123149810