Assign T-Code for WDA

Dear All Gurus,

I have assigned a T-Code for a webdynpro program created as per below instructions (URL). Tcode is working fine but I need to RE-ENTER user name and password every time when I enter T-Code.

Can you advice on this.

http://wiki.scn.sap.com/wiki/display/WDABAP/How+to+Create+a+transaction+code+for+webdynpro+application