Desktop entries of apkenv are stored in /home/user/.local/share/applications (actually, any custom desktop entry can esily be stored here). You will need a basic text editor (like nano or khtsimpletext) to modify them. Once you succeed to open one, the structure of them is so obvious, that you won't need any further explanation about what to do. It is also easier to me, to create directly the entry there rather than using the apkenv --install command.