How to access part parameters from assembly ?

Hello guys!

Can someone give me a simple example please.

Assembly document

     - FRONT_BEAM

     - REAR_BEAM

     etc....

Need to know how to change FRONT_BEAM parameter ("DF_X_Offset@Sketch1") from an assembly level?

For single part its easy,

' single part

swApp = Application.SldWorks

swModel = swApp.ActiveDoc

swModel.Parameter("DF_X_Offset@Sketch1").SystemValue = DF_X_Offset * 0.0254

but how I tell via code get FRONT_BEAM and change DF_X_Offset@Sketch1@FRONT_BEAM???

Any help is appreciated.

Thank you.

SolidworksApi macros