How to deal with a helical joint or screw pair joint when assigning DH paramete

[mikealpha85]

Hi all
I have a helical joint( screw pair ) and I need to assign the DH parameters to it , to start with the forward kinematics . I was thinking of using a revolute joint series with a prismatic joint ( i.e. compound joint ) but should I treat them when assigning coordinates as separate joints ( revolute joint number 1 , prismatic number 2 ) an advice here would be invaluable .
Thanks Everyone