Accordingly with new SimVimX custom plane conversion format the RSC online conversion tool has been updated and, as it was announced, now it's merged into RSC Configurator.
Conversion menu for a parameter is opening by clicking on its assigned pin in the configurator (if a plane conversion is created and selected), and you can switch between making conversions for several aircraft models by selecting them in the "Conversion" menu.
The built-in conversions (included into the SimVimX.dat and RSC_Planes.dat files) remain as-is.
If you have the old conversion ".dat" file you need to load in the new configurator's "Conversion" menu. It will be included into configuration and automatically translated into the new format. For more information read the Conversion Guide
and Generic I/O