The problem was the wrong/old Template from the ClientDataSet
.
To create a new template:
- go to Designmode and select the
ClientDataSet
. - Right-Click and 'Create Dataset'.
- Select 'Save to MyBase Xml UTF8 table...' and save the new generated xml.
With the new generated Xml the fields are recognized correctly and as @ArnaudBouchez already mentioned, there is no need to decode the stream.