How to send a SMS to a specipic phone port

Hi All,

how to send a SMS to a specific phone port, eg. 50000(port no in mobile)

Please help me on this, i have created few games using J2ME, anyone can download the games , but to activate they have to request a serial key via SMS, request SMS comes from mobile port number 50000 and also i want to reply the sms back to same mobile port using a gsm modem, can some one please help me on this one.

how to set a reply / destination port no for send sms.

thanks in advance.