You are misreading the bugzilla discussion, as that is only possible by self-compiling the eclipse launcher source (with a modified rc file).
However, there is an alternative: You can patch the launcher executable manually (using any kind of resource editor) and then put it into your product as root file. This works with tycho, I use that approach. The drawback is of course that this executable will not be updated, if you change branding details in the product definition file.
Alternatively to a root file you could also overwrite the launcher executable during an installation creation (outside of Eclipse). E.g. we create an NSIS installer around an RCP app and can also modify it there.