I'm experiencing an issue whereby if the first value of a given column of an xml table read into Flex via the HTTPService has a value of 0 or 0.0 this value then gets cast to a string in the underlying ArrayCollection. Thus, when I pass this ArrayCollection to my AdvancedDataGrid the column in question can only be sorted as if it is a string. Is this a known bug in the HTTPService? Does anybody know of a workaround? If the first value of a numeric column in the underlying xml is non-zero the sorting works perfectly fine. It appears that the AdvancedDataGrid decides the datatype from the first entry for a given column.