[pstricks] How can I make a double line with no color in between?

[Luis Sequeira]

> I cannot see the sense of an opacity for the innerline
> and not the outer line. However, define an inneropacity
> and \tx at setInnerStrokeTransparency and modifiy the macro
> \pst at doublestroke

I have a presentation with a background that has a gradient in it. 

I want to connect several pairs of nodes with a double line to emulate "equals" sign.

(If I had a solid background I could just fake it by using the background color for the inner part)

I may try your suggestion. Thank you again.

LS