OK, I've tried it and couldn't get them to work on my TomToms either
First I tried adding the compiled complete voice files data75.chk and data75.vif.
As you say, it appears for selection in the "Change voice" menu, but there''s nothing heard when you tap "test" and there's nothing heard on a demo route when you've selected your voice.
So next I was going to try compiling a fresh version from your individual .ogg files, but I thought I'd look at one or two files individually first to check they were recorded at the right sample rate etc.
I COULDN'T OPEN THEM.
I've tried in Adobe Audition and in Audacity and neither program will open them at all, they don't recognise them as audio files and if I import them as raw data, I just get digital shash.
So the next questions I think have to be...
1. how did you record your daughters voice? (i.e. what program, and to what file format?
2. what did you use to convert the files to .ogg format (if you didn't record and save to that format in the first place?
3. Can you play back your original files in whatever program you used to record them?
Audacity is a good prog. to use, mainly because it's free! You can record straight into it and export to ogg format, but if you need any help with it, just shout.