Sorry for the missing details. For my first tests, I've used the SSIS Wizard with PGNP as the destination connection. In the Advanced Properties for that connection, I selected "Copy command" for the "Bulk Insert Method" property.
Then I selected a table containing a tinyint (DT_UI1) datatype column, and checked the box to drop and recreate the destination table in the Column Assignments dialog box, because the table was already copied before.
After that, running the package results in an error with the message: "Convertion of type 17 to string failed (bt=2, ord=15, tbl="MY_TABLE")"