callto: or tel: to call phone number on mobile device

Dear community,

referring to this discussion; Linking Design Studio apps to MS Outlook I was wondering if it is possible to start a phone call out of a Design Studio application on a mobile device.

I tried it similarly with

APPLICATION.openNewWindow("tel:+4912345");

and

APPLICATION.openNewWindow("callto:+4912345");

but both did not work. It should work for iPhone / iPad.

Has anyone ideas how to solve it?

Thanks in advance,

Daniel