I have to upgrade a Database from a DBF to SQL Server where some tables structures were changed.

In a scan..endscan I'm trying to build a string with the values from the VFP tables and then call a SP
to insert the values in SQL for each record.
In a function that builds the string for each record of the table and later calls a SP sending the string with the values.
All works fine but when I have empty Dates I replace the value with NULL, but when I execute the SP using SQLEXEC(), I get an error message telling the Date parameter was not suplied.
Any Ideia how to send empty Dates to SQL SERVER so it doesnt stores 01/01/1900 in SQL SmallDatetime.

Thanks in advance.

Peter

&& x_campos = AFIELDS(aCampos)

FUNCTION Monta_String_SQL  && sample
LPARAMETERS x_campos
PUBLIC cSQL
cSQL = ''
FOR nCount = 2 TO x_campos			&& N° of fields of the table
	cNome_campo = aCampos[nCount,1]	&& Name of field
	cDado = EVALUATE(aCampos[nCount,1])	&& Value of the field
	aTipo = aCampos[nCount,2]		&& Type of field
	aTamanho = aCampos[nCount,3]	&& Size of field
	aCasasDec = aCampos[nCount,4]	&& Decimals...
.
.
	IF aTipo = "N" OR aTipo = "Y"
		cDado = STR(cDado,aTamanho,aCasasDec)
	ENDIF

	IF aTipo = "B"
		IF aCasasDec > 0
			cDado = STR(cDado,aTamanho,aCasas)
		ELSE
			cDado = STR(cDado)
		ENDIF
	ENDIF
.
.
* Problem Here !
	IF aTipo = "D"
		IF EMPTY(cDado)	&& p/ campo sem data ficar sem data no SQL
			cDado = 'NULL'
		ELSE
			cData = DTOC(cDado)
			cDado = cData
		ENDIF
	ENDIF

	cSQL = cSQL + "'" + cDado + "'"+ ","

ENDFOR
cSQL = SUBSTR(cSQL,1,LEN(cSQL)-1)	&& removes the last ','

cSQLString = "EXECUTE SPA_INS_Table_x " + cSQL
IF !SQLExec(nID, cSQLString)>= 1
 =AERROR(mERRO)
 ?mERRO(1,3)
 ?mERRO(1,5)
ENDIF