How can I add a second contact to a deal with the mobile App?

How can I add a second contact to a deal with the mobile App?

With the web version of ZCRM I can add a second contact to a deal (via contact roles). When I use the Android CRM App I did not find a way to achieve this. I cannot edit contact roles and I cannot even add a second contact at all, let alone change the primary contact. When I add a contact to a deal, the previous contact is lost.

Can you please help me find that feature or otherwise can you please put it on your list of requested features?

thank you,
Oliver