This script will generate all Table and Column comment statements.

1) bring up the Script Explorer (tab at bottom of Model Explorer)

2) right click on "User Defined" and select "New Script"

3) copy/paste the script below into the edit control

4) hit the run button (the first icon in the toolbar above the edit control)

/********** start of script *************/

' Write comments for table and its columns
Sub Evaluate_OnLoad()
	Set Context = CreateObject("SCF.ScriptContext")
	Set Document = Context.ScriptDocument
	Set Script = Context.Object
	Set Options = Context.Options
	Set Model = Script.Model.AsObject
	For Each Table in Model.Children("Table")
		If Table.Property("Comment").AsString <> "" Then
			Document.Write("COMMENT ON TABLE ")
			Document.Write(ObjectName(Table, Options))
			Document.Write(" IS '" & Table.Property("Escaped Comment").AsString & "'" & Delim(Options))
		End If
	    For Each GenOrderProp in Table.Property("Generation Order").AsVector
		    Set Column = GenOrderProp.AsObject
			If Column.Property("Generate").AsBoolean Then
				If Column.Property("Comment").AsString <> "" Then
					Document.Write("COMMENT ON COLUMN ")
                    Document.Write(ObjectName(Table, Options) & ".")
					Document.Write(QualifiedName(Column, Table, Quote))
					Document.Write(" IS '" & Column.Property("Escaped Comment").AsString & "'" & Delim(Options))
				End If
			End If
		Next
	Next
End Sub