I haven't tried this with the real-time engine, but on a PC you would get a reference to the VI (let's say by using open VI reference) and wiring that reference into an invoke node with the Run VI method selected. Set Wait until done to F to allow your VI to continue running. Both functions can be found in the Application Control palette. If this doesn't work, you can simply place your VI inside a case structure inside a loop which waits until a flag is recieved to run the VI. Set the flag when you recieve the command.
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