hi leo,

are you using Ext3 or 4? The store will always override metadata on load (which generally makes sense); however, you can investigate one of these depending on your Ext version:

1) In either Ext version, listen for the Store's load event and iterate the records to make changes. this is less efficient, and I dont think there is a guarantee your listener will be called before other load listeners, but by far the easiest.

2) Either the store or reader should have an event that is something like 'metadatachange' (this name might be incorrect'), which is triggered when metadata loads. Your handler is passed the fields metadata object and you could modify it accordingly. This is sorta digging into the guts of Ext to make this work, but it is relatively clean if you get it working.