See this feature request also.

I don't believe this is possible. I know you can do something similar by creating a field and then evaluation the option from the field. I understand it would be nice to have the additional buttons. I would have to check if something changed for version 10.2.

I need this too! It's not in Ver. 10.2.

Forms 11 Update 3 has added support for more action buttons on user tasks.

You can see other changes of Forms 11 Update 3 from  https://support.laserfiche.com/kb/1014413/list-of-changes-for-laserfiche-forms-11-update-3 and get Forms 11 Update 3 from Laserfiche 11 package  https://support.laserfiche.com/kb/1014263/software-versions-and-fixes-included-in-the-laserfiche-11-download-package.