I am using a Vive and I can't see my controllers too by default. I have to change the openvr_api.dll with the latest from steam.Also, I'm having no luck with it. My controllers aren't showing up in VaM (works fine running Half Life Alyx)
Find ".\VAM\VaM_Data\Plugins\openvr_api.dll" in VAM and make a backup.
Copy the newest ".\Steam\steamapps\common\SteamVR\bin\win64\openvr_api.dll" from steamvr.
Paths may be different in your end.
Enable controllers in VAM (VR1 tab).