Hello Thomas,
I am not sure what exactly you mean by "We want to open a new SC in SRM with fullscreen mode (SRM 7.02 with classic scenario to ERP 6.0)."
Are you talking about the layout the Shopping cart Screen . You want to open the SC screen in full mode. Correct me if I am wrong. If that's the case then please contact your Portal Consultant and ask him/her to maintain the setting for the layout . Once done then you will be able to see the SC screen in full mode.
Thanks
Gaurav Gautam