I think indeed that the best solution is to manage it through a quick and dirty script as I tried the following but its non sense!

 Code:
$bday = "monday", "tuesday", "wednesday", "thursday", "friday"

If AScan($bday, @Day)
	; Business day/Workday
	If @MDayNo = 2 ;That is false
		; Business day/Workday
		? "2nd business day : @Day - @MDayNo - @Date"
	Else
		? "not 2nd business day : @Day - @MDayNo - @Date"
	Endif
Else
	? "not a business day / workday : @Day - @MDayNo - @Date"
Endif