If you have the enterprise ipa installed, then the name should be "App Portal" when selecting from the list of apps in the Home Screen Layout payload. It could be that you have the webclip installed, not the actual app (which is what by default gets deployed on enrollment). If you'd like to deploy the enterprise ipa, you can download it from
(current version as of writing this). When this is installed, the ipa will swap out the web clip and then you will be able to select the app from your Home Screen layout payload.
Regarding web clips and home screen layout... unfortunately they are not supported on the home screen layout payload because of the fact that the identifier cannot be globally unique.