Update on the issue, in the absence of any response!
I came to know from a person working in Siemens that the iOS app doesnt support this feature.
As it was quite important for my project, I used a Microsoft Surface Pro 3 and installed the windows version and solved the issue.
yes you are right JT2Go for Desktop is much better than all mobile JT2Go versions.
You can clip, you have an better site and button bar and much more other options are included.
I will most test the desktop version before I try to use one mobile JT2Go app.