Here's a weird one: Riding your eyeball as a mount

[DrChickenbeer]

As a mesmerist eyebiter, you can have your eyeballs detach and float around. Your eyeballs are considered familiars. If you play a small creature and use the mauler alternate racial trait on your eyeball (which is counted as a familiar, even in Hero Lab), you should be able to make the eyeball a medium creature.

Ignoring all of the reasons why this is a bad idea, why won't Hero Lab allow me to apply the mauler template? It says it can only be applied to familiars, but it won't work on my eyeball familiar.

Any ideas?