error read a Text UserField from DbDS

Hi to all

I have a userfield in document line, and the type's field is text (Long text 64000 Char)

I write the field:

m_Dbds.SetValue("U_IDE_XML", iRow, "My Text")

But I cannot read:

xml = m_Dbds.GetValue("U_IDE_XML", l_iRow)

because have the error: 'Data Source - Bad Parameters'

Note: the value appear on the matrix.

Thank you

Andrea