This is a script that generates the DDL for each Schema to a seperate file. 

To run it:

1) bring up the Script 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 *************/

Sub Evaluate_OnLoad()
	Set Context = CreateObject("SCF.ScriptContext")
	Set Document = Context.ScriptDocument
	Set ThisScript = Context.Object
	Set Model = ThisScript.Model
	Set Framework = CreateObject("SCF.ScriptFramework")

	' Create the File System Object
	Set FSO = CreateObject("Scripting.FileSystemObject")

	File = Context.FileName
	Dir = FSO.GetParentFolderName(File)

	' Create the Folder specified by strDirectory on line 10
	If Not FSO.FolderExists(Dir) Then
		FSO.CreateFolder(Dir)
	End If

	For Each Schema In Model.AsObject.Children("Schema")
		' arg 1 - optional name of Model Subset to filter by - defaults to none
		' arg 2 - optional name of Option Set to use - defaults to model's current
		' arg 3 - optional name of Schema to filter by - defaults to none
		' arg 4 - optional name of storage container/Tablespaces to filter by - defaults to none
		DDL = Model.DDL("", "", Schema.Name, "")
		If DDL <> "" Then
			strFile = Dir + "\" + Schema.Name + ".sql"
			Document.Write("Created DDL for Schema " + Schema.Name + " in file " + strFile + vbNewLine)
			Set ControlFile = FSO.CreateTextFile(strFile)
			ControlFile.WriteLine(DDL)
			ControlFile.Close
		End If
	Next
End Sub