International SMS not posting for me

I have a UK mobile number. I have already sent in my verification code via SMS (received no response), and then tried posting via SMS, but it is not working. After waiting several minutes, it is still not showing up in my recent posts. Do I need to enter in my UK mobile number in the "Mobile #" field at http://ping.fm/sms? I tried putting it in, but it got truncated to 10 digits, which made me think it was only intended for US/Canada numbers.