Problem Importing Keywords with jpg photos into Library

Question

I am a new and enthusiastic LR user working to migrate from iMatch, where I have kept my ~80,000 photos organized for the last several years. However, my last roadblock to being able to do that is the import of keyword information (or as iMatch calls them, Categories). Obviously it's critical that these transfer across seemlessly as they represent untold number of hours in sorting and managing the database.
The situation: Via an iMatch script I can successfully write the associated categories, including hierarchy, into an IPTC field of my choosing that is then included with the jpg file itself. I have done this into the "Keywords" field, with various combinations of special characters and/or spaces to denote hierarchy relationships or separate keywords.
Upon LR import: LR recognizes the presence of the keywords and pulls them into the metadata, but refuses to see them as anything except part of one continuous hierarchy.
Example: A picture in iMatch has two Categories associated with it, both of which are organized under a parent-->child hierarchy:
Trips --> Switzerland2006 and Special --> Family --> Daughter
When written via script into the IPTC Keyword field of the jpg file, it looks like this: Trips.Switzerland2006; Special.Family.Daughter
(note -- I can make the semicolon separating the keywords anything, such as a comma, space, etc. I have tried all.)
When imported into LR, it ends up looking like this under the left panel Keyword Tags area: Trips --> Switzerland2006; Special --> Family --> Daughter
In the righthand panel under "Keyword Tags", I only see "Daughter" as this is at the bottom of the single stack hierarchy that was interpreted.
In other words: I have found no possible way for LR to recognize that there is in fact MORE THAN ONE keyword coming in, rather than always a single hierarchy stack or very long words with spaces, semicolons, whatever included in between.
I have tried every setting under Preferences-->File Handling, but those only give me options about when to tell LR to recognize a hierarchy step, not about what character to see as a separation between keywords themselves.
Final note: If I first open one of my picture files in Adobe Bridge and look at the IPTC field Keyword there, it looks perfect. And if I go into that field and mess around a bit -- add a space, take away a space -- with in the end no change, then resave the file, THEN bring into LR, it works fine! I believe what is happening in this case is that Bridge is correctly interpreting the Keyword data from the file, but then is writing it into an XMP area that I can't see. LR must then read the XMP area in preference over the IPTC are upon import.... But -- if Bridge can read the original IPTC line correctly, why not Lightroom?!
Bottom line question: What format or special character or special trick must be used for multiple keywords in the IPTC Keyword field so that Lightroom will correctly recognize the multiple keywords upon import?
Thank you!
JMC

Answer 1

Do those keyword hierarchies show up properly in Vista Photo Gallery? I have the LR Edit/Preferences/File Handling configured to treat "/" (which is what Vista Photo Gallery uses) as a keyword separator and LR recognizes the hierarchical keywords.
As I understand it, Vista reads both XMP and IIM/IPTC Headers, but will write only to XMP. I forced Photo Gallery to convert my keywords to XMP by adding a global keyword and then deleting it later. Then I used drag and drop to recreate the hierarchies. It works for me.