Globals as default input for a method.

No, you cannot do that. You can use a Const as a default input, but not a Global. Like this:

Const test = 1

Type t
	Method a(b = test)
		Print b
	EndMethod
End Type

Another alternative is to use a redundant default parameter (ie. one which you know is incorrect), and then replace it with a global. This isn't exactly nice, but it works:

Global test = 1

Type t
	Method a(b = -9999)
		If b = -9999 Then b = test
		Print b
	EndMethod
End Type

[edit] DOH!