Messege Protocol : SOAP protocal receiver !

I am tryin a scenerio where the receiver has a Transport Protocol as SMTP and messege Prortocol as SOAP 1.1.

My network has a intranet feature, I know the intranet IP address, and I am gettin an error in the comunication channel : call failed.

In teh target url I hav used :

http://www.siprod.net/webservices/xemail/xemailwebservice.asmx

and SOAP action as

http://www.siprod.net/webservices/XEMail/SendSmtpEMail

Kindly suggest, what do i got to do so as to get out of this intranet issue/ may me this is some kind of firewall!!

Regards

Arnab