You shouldn't need to have the password as long as you retain a signed copy of the PKG file with the current key (whatever it is) -- You can re-key using that prior signed package.
FYI, I've suggested (to my Roku overlords) 4 different possible plugin changes to address this issue - just waiting to see which way we're going with it.
In the next version of the plugin to be published to the update server, the password fields in the export/deployment dialog will show asterisks by default, but will also have a toggle button in front of each to allow the cleartext display of the password as needed.
Thanks for looking into this so quickly.
I updated to the latest version tonight ( BrightScript Core 126.96.36.199408081014 ) but I don't see the new checkbox for showing the password. The deployment panel looks the same as before, with the password still starred out.