If you write a plugins in .Net and want to make this app available in BricsCad after startup seems the most reliable way is to add following keys to you Registry:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Bricsys\ObjectDRX\V21x64\Applications\YourApplicationName]
"Loader"="C:\\Temp\\YourAssembly.dll"
"Managed"=dword:00000001
"LoadCtrls"=dword:00000002
"Description"="Your description"Where LoadCtrls = 2 is loading at startup.
Seems there is not much info about Registry structure details at documentatation but there is some:
and this one is about how to get/set BricsCAD templates and references folders:
