Create accurate Kindle Locations value for a custom column.

[juston]

Hi Guys,
I have a series of books that I have imported into my Calibre library. The books all have METADATA that I wish to keep. However, each of the books have been named in the following manner:

title - author - ASIN - kindlelocations.mobi

These books have been formatted for the HP TouchPad webOS KindleImport app.

The internal METADATA is sufficient for my needs except that there is no way that I can think of to generate the kindlelocations value within Calibre.

My initial thought was to import the books and then read the filename into a custom column and extract the kindlelocations value with a regular expression.

However I now realise that the import process renames the files in the Calibre library storage area based on the METADATA. Consequently the original file is no longer relevant to the library or to Calibre. As such I now have two new questions:

(1.) Is there a function, plugin or method to accurately recreate a kindle location value for a mobi book within Calibre?
I believe (though I may be wrong) that the kindle location value is calculated from the unpacked source of the text portion (including all of the formatting and markup) of the mobi file divided by 128, such that each location is 128 bytes long.

I have used Count Pages Plugin (which is great) but it is impossible to use it to give an accurate locations count as the locations count is a function of the text size including the markup language tags.

(2.) If there is no function/plugin/method to create the kindle locations value. Is there a way I can import meta data from a text file into a custom column for a book that already exists in calibre?
If this is possible I can use the original file list - use a regular expression to match the original file with the title of the imported book and parse for the kindle locations (created by m0ngrels script) for import into a Calibre custom tag.