silva metadata: changing properties

dear developer

using the workaround for listfields in my self-made metadataset which 
guido suggested last week (did i already mention that i don't like this 
workaround;-) i categorized all my sila documents. today i found out 
that i made one of those silly typos in the listfields :-(

it is not possible to just correct the typo in the metadataset because 
now, silva throws up a zope error every time when looking up the 
properties tab. apart from recreating all documents the only workaround 
i've found so far was to reinsert the list element with the same typo, 
add an additional element without the typo, reassign all properties to 
the element without the typo and then, at the very end, remove the 
element with the typo from the metadataset. needless to say that this 
is very inconvenient for large sites and sites with many self-made 
metadatasets/elements (e.g. eth zurich). metadatasets can evolve and 
change with time...

instead of a zope error, could you catch this error and display a 
message such as "sorry, because of an error the properties have been 
reset. please reassign the proper values." and reset all properties of 
all self-made metadatasets to the default or inherited ones. maybe you 
know exactly where the error occurred and you could reset this metadata 
element only and inform the user about it. maybe there is an even 
easier way to solve this problem?

regards,
marc