Abap calling webservice

Hello Friends

I need to call a webservice from Abap.I created a proxy object specifying URL of the webservice,but its giving the following error :

"ICM_HTTP_CONNECTION_FAILED"

Guide me to resolve this.I m working on SAP-WAS 6.40

I have gone through various sites .whats the step-wise procedure to call webservice,from Abap.

Regards

Dhanya.R.Nair