A little mess in replacing audio track

[Instant Martian]

Hi guys,
this is the story: I recently bought the long awaited 2-Disc Special Edition of "Grease", one of my favourite movies.
There was already a single disc edition here in Italy but I waited for this new set.
Sadly Paramount has decided not to keep the original (i.e. theatrical) Italian audio track and put a new DD 5.1 re-dubbed track.
For "sentimental" reason I wanted to have the original dubbing so I had to buy the old edition too, which has it, although in a mono track.
The new edition has 3 audio tracks:
- 5.1 English
- 5.1 Italian (re-dubbed)
- 2.0 English (director's commentary)
What I am trying to do is to replace the "useless" 5.1 Italian track with the mono track from the old edition.
I went through all the demuxing/remuxing stuff with PGCDemux and VobBlanker and I succeded but there is a problem.
At the very beginning of the playback there is a menu with two buttons (it had more but I worked it with MenuEdit)
- English
- Italian
If I choose Italian the movie should start with Italian audio but I hear the director's commentary instead.
In other words, I managed to replace the track but I have messed up something and now there is no more correspondence between selected and played audio.
Is there a way to fix that?

[Instant Martian]

Nothing?

[Instant Martian]

I worked on it and I am almost there.
I succeded in replacing the audio track and set the default audio with PgcEdit.
I edited the menu bitmap and menu subpic too.
But I can't fix subtitles.
This is the PgcDemux log of the movie, after a passage through DVDShrink to strip out all the useless subpictures:

Subs_01=None
Subs_02=None
Subs_03=0x22 English
Subs_04=0x23 English
Subs_05=None
Subs_06=None
Subs_07=None
Subs_08=None
Subs_09=None
Subs_10=None
Subs_11=0x2A Italian
Subs_12=0x2B Italian
Subs_13=None
Subs_14=None
Subs_15=None
Subs_16=None
Subs_17=None
Subs_18=None
Subs_19=None
Subs_20=None
Subs_21=0x34 English (commentary)
Subs_22=0x35 English (commentary)
Subs_23=None
Subs_24=None
Subs_25=0x38 Italian (commentary)
Subs_26=0x39 Italian (commentary)
Subs_27=0x3A English (Karaoke)
Subs_28=0x3B English (karaoke)
Subs_29=None
Subs_30=None
Subs_31=None
Subs_32=None

If I play the DVD I have 5 subs:
- English
- Italian
- English (Director's commentary)
- Italian (Director's commentary)
- English (Karaoke)

This is the PgcEdit subpicture panel:

Everything works fine.
After I replace the Spanish track with the Italian one (remux the movie with IfoEdit and "replace" with VobBlanker), the PgcEdit subpicture panel remains the same (as in the picture above) but there is no more match between the subpictures and their "labels" in PowerDVD.
First question is how can I fix that?
Second question: in the log there are 10 subpicture tracks but playing the disc I have only 5 tracks. If I understand it well, for each track there are actually two tracks (one for the widescreen format, one for letterboxed format).
PgcEdit uses one single slot for each couple of subpictures.
Do I have to do the same or use two separate slots, one for each track?