[Zope] Meta Type change

[David]

Hi

How do I change the meta_type for an object in the ZMI from within Zope?

An instance of a product I have built (inheriting from the the Folder 
Product) has become inaccessible after adding a lot of data. 
Essentially this is a product to archive text strings in a specific 
format and has worked fine for months. The problem has lead to 
corruption of the Data.fs file (and fsrecovery.py did not find anything 
to recover). I had a few backups from which I was able to recover the 
rest of the site and of the archive in a previous state, but had to go 
back 3 days.

The backup from the day before the corruption does have the object in 
the ZMI tree, but now Zope thinks this is a normal Folder and when I 
try to access it, gives me attribute errors.  When I attempt an XML 
download, although there are errors, I can see all the archived texts 
in the text that is appearing in my browser, however they are embedded 
in chaotic-looking text garbage, so I can't find a way to extract them 
by script. (And there are about 5000 missing texts, so copy and paste 
would take days!)

I was wondering if I could just alter the meta_type for the object from 
within Zope, maybe through a python script and see if that makes the 
object accessible again. I can't find anything on how to change the 
meta_type for an existing object though.

Any help very appreciated.

Cheers

David