I'm just trying to help you. I don't work for JRiver. I'm just another user. I'm sorry I don't know much about integration with itunes. It's just not something I've worked with as I prefer not to. This from someone who uses a Mac as his primary computer.
I think the root of your problem is deeper, but I'll answer your how to remove leading numbers question.
There are several ways to do it. Let's pretend that ALL of the Name fields look like this:
1-01 Song Name Here
If that's true, you would just want to remove the first 4 characters from the [Name] field. To do so, you can use an expression like:
=removeleft([Name],4)
I would try this as an expression column first:
Go to a view where you can see the [Name] field for a bunch of files.
Right click on the header and select Add Expression Column.
In the expression editor, paste in the expression above.
Look at the Expression Column and make sure that it has the correct song name in it now.
If that works for all of your files, then you can paste the expression into the Tagging Pane like this:
Select some files.
Right click and choose "Tag".
In the Tagging Pane on the left that pops up, go find the Name field. It should be near the top. Since you have several files selected, it should say [Varies].
Click in the field and paste in the expression.
Now all of the Name fields should change, removing the first 4 characters.
If it doesn't work properly, press control-Z, or Edit > Undo .
If your Name fields have more complicated issues, they can probably be fixed with more advanced expressions.
I hope this helps.
Brian.