mp3 gain to itunes norm

some times I add a track to itunes THEN run mp3gain
I saw tha thtere is now a function to go from replay gain to itunes norm
is there a similar way to go from mp3 gain to itunes norm or even
mp3gain to replay gain

never mind. I did not realize that mp3gain did write the replay gian header field.
I simply need to run mp3 gian and then use the soundcheck function