I believe this is what you might be talking about. I asked Van's support about this since it used to be a part of the lighting kit. (DWG 40-14) I just purchased the lighting kit to add it to my RV-12 and noticed it was not included. This is their reply as to why it is no longer part of the lighting kit.
"The F-00002 was found to be ineffective and potentially cause higher temperatures, no longer recommended. We do have a different voltage regulator option if you would like to install it during your build but is in no way mandatory. New kits sipping today will have the new regulator." cost for the regulator and installation kit is $495
pages 46-19-21 show the installation of the SH regulator on the current RV-12
This might be the post you were looking for?