Was simpler than that.
When you install B4A Beta, it install by default to the same v4.30 directory, although it ask for new desktop icons, if it founds the shortcut exists on the desktop, it does not overwrite it, leading the desktop icon pointing to Basic4android.exe and not to b4a.exe.
That was all, now working as a charm. Keep you posted if I found any bugs.
Thanks
FBP