I will be the first to admit that I know very little about mobile telephones and text messaging - but this seems very strange to me.
I took my Motorola "World Phone" to Ukraine where I bought a SIM card. I used the phone quite a few times to send text messages to others. On my way back - I still happened to have my phone on and it worked in Germany (for SMS). Curious, I decided to try it in the USA - Wisconsin and had a Ukrainian friend send me a text message on my Ukrainian number as if I was over there. I RECEIVED IT!
Now I cannot send with it. For that I rely on my computer and web based "Free SMS" sites. But I get all my replies on my Ukranian number - on my phone in the US.
jet, do you want me to bring back some more sim recharge cards from Ukraine for your sms? :))
One time in Kiev, a friend and I had phones from different countries and we sms messages
and we were right next to each other. From ukraine to US to Europe to Ukraine for each message.
that sim you bought, I presume prepaid, must have been allowed 'roaming' i.e. using foreign networks with which the issuing network has a contract with. It'll work on & via the bigger networks in most of the world.
If you, at home with your local sim on your own network, cannot send sms's you have your phone set-up wrong. Call your network to get the correct details like for instance the number a sms has to be sent to, or rather 'through' (kinda server).
Oh, and that Ukrainian sim quite likely had these parameters already aboard hence your phone will work there - your sms's are routed via the Ukrainian switch.... which means that your own sim, once in your phone, will send to same switch instead of that one from your own network. No rocket-science, just phone your service dept. to get the various parameters.
Mind you, I presume your network is a GSM, not analogue I mean?