@Moderators: Please ban Imogenering. It's a bot/jerk that retranslates previous posts.
Not a bad idea tho.
Your last chance would be to check whether the BitDefender program accepts command line parameters - and if yes, define an internal association (additional verb only) to call BitDefender with the file to check.
The tcmdx64 tool loads all 64-bit shell extensions and asks them to return their context menu entries. That's how most externsions work. However, there seem to be some extensions which list menu items in the registry, so the Explorer can grab them from there. TC does not currently support this method because it's badly described, and I have never seen an extension which uses it. Maybe BitDefender uses this method.
I posted a reply in the BD forum thread (cannot post link - it's the one above in the karnin previous post).
Our extensions do not list commands in registry. For x86 issue, most likely is registered only the x64 extension (so explorer 64-bit, which is default, is loading the extension, while TC 32-bit I suppose does not load 64-bit extensions).
Also - at the time when I wrote BD file vault extensions - I noticed TC does not specify the directory in CMINVOKECOMMAND(EX) lpDirectory(W). File Vault have special code to get the directory. Not sure if this is an issue now (I wrote FV in 2007...).
There is already a ticket - I learned today about it... - and we're on it. Stay tuned.