AUs are not recognized by GB / Defaulting to Pro-Tools. How do I change this?

I'm a novice at GarageBand, having only messed around in recording a few tracks. Yesterday, I downloaded two amp simulator demos (S-Gear and TH3) and specifically chose the demo versions that are not designed to work with Pro-Tools/iLock. Today, I tried to use the amp sims as AUs in GB, and I couldn't find them.

In trying to figure out what's wrong, it seems that the files/folder appear in Library/Audio/Plug-Ins as Pro-Tools plug-ins.

Some years ago, I bought an M-Box which came with a version of Pro-Tools. At the time, the install instructions implied (to me) that installation of Pro-Tools was required to operate the M-Box. I was happy to install Pro-Tools (hey! free software!) but found the the iLock was a nuisance and the actual software was impractical for me, compared to GarageBand. I haven't used Pro-Tools, since.

I'd prefer not to uninstall Pro-Tools (hey! free software!), but I don't want it to be the primary DAW. How can I change this?

Also, is there a way to modify/move the amp sims that I'm demo'ing, to get them to work with GarageBand?

Any other ideas?