Unfortunately it does not handle system data types like UserId very well. You have to change the \\Classes\SysEDTMigration to prepare the tool for all types:
public boolean migrateToNewRelation(
tableName _tableName,
fieldName _fieldName,
SysEDTMigrationEDT _edtInfo,
boolean _deleteAction)
{
(...)
fkTableNode = TreeNode::findNode(strfmt('%1\\%2',#TablesPath,_tableName));
edtNode = TreeNode::findNode(strfmt('%1\\%2',#ExtendedDataTypesPath,_edtInfo.Name));
//--> WIK
if (!edtNode)
{
edtNode = TreeNode::findNode(strfmt('%1\\%2', #SystemTypesPath, _edtInfo.Name));
}
//
You can find more details on MSDN about the EDT Relation Migration Tool:
http://msdn.microsoft.com/en-us/library/gg989788.aspx
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