How to disable gui messages?

Hello,

How can I disable GUI messages during import?
I am working on Nav 2009 R2 and created an xml port to import sales invoices and during import, I get a message it says You may have changed a dimension. Do you want to update the lines? I do not wish to see this message.

I traced the code and saw that salesperson onvalidate calls update dimensions function from table 357 Document Dimension. It checks for GUIALLOWED or not. I know GUIALLOWED is not property but is there anyway I can set it false? The code below didn't work for me

Ok := GUIALLOWED;
Ok := FALSE;

so I changed the source code in table 357 document dimension, added sethidevalidationdialog but still no luck,

IF UpdateLine <> UpdateLine::Update THEN
  //IF GUIALLOWED THEN (orj code)
  IF NOT HideValidationDialog AND GUIALLOWED THEN 
    IF ShippedReceived THEN BEGIN
      IF NOT CONFIRM(Text006,TRUE) THEN
        EXIT
    END ELSE
      IF NOT CONFIRM(Text003,TRUE) THEN //this line cause a problem
        EXIT;


Text003	You may have changed a dimension.\\Do you want to update the lines?