Old thread I know, but hopefully it will help someone:
I have worked out how to use the Lexicon MX400 vsts properly in Cubase. Firstly you need to buy and install Jbridge and follow all the instruction to use Jbridge. The recommendation is that any ‘bridged’ vsts go in their own isolated folder. and scan them in the usual way.
This alone will not make them work. You need to do the following for both the Lexicon A and Lexicon B plugin:
Open Cubase with a track and insert the Lexicon A vst. On the Jbridge window, there is a settings button. Click this and a bunch of tick boxes appear. At the bottom there is a button to open the settings file (Which is just a notepad file). Click this and open it up. Rread the settings and change the line “RUN_IN_EXISTING_AUXHOST 0” to “RUN_IN_EXISTING_AUXHOST 1” and save the settings file.
Remove the plugin and do the same thing for the LEX B vst.
Then restart your Cubase and voila! you can use both vsts together.