I'm using this function and works very well.
Example:

Select * from myTable;
into cursor curTest

EditCursor()

or:

EditCursor("curTest")


************************************************************
* Torna editável um cursor gerado pelo comando SELECT-SQL
************************************************************
FUNCTION EditCursor
LPARAMETERS lcCursorAlias
LOCAL lnWorkArea, lcTmpDbfName, lcTmpCur, lnCurArea
IF Parameters()=0
lcCursorAlias = Alias()
ENDIF
lnCurArea = Select()
SELECT (lcCursorAlias)
lnWorkArea = Select(0)
IF At( ".TMP", Dbf() ) > 0
SELECT 0
lcTmpDbfName = Dbf(lcCursorAlias)
USE (lcTmpDbfName) AGAIN
ELSE
SELECT * FROM ( Dbf(lcCursorAlias) );
INTO CURSOR lcTmpCur ;
WHERE .T.
lcTmpDbfName = Dbf( "lcTmpCur" )
ENDIF
USE (lcTmpDbfName) AGAIN IN (lnWorkArea) ALIAS (lcCursorAlias)
USE
SELECT (lnCurArea)
RETURN