CorelDRAW X3 :: Postscript Halftone Screen Using Paint Tool / Uniform Color / Options / Postscript

I require an equally spaced fine line shading in an extrusion.  I will take you through my process and then get to the problem.

I create an object (usually curved text), extrude it and  break the extrusion apart;  then I use the fill tool and open fill color dialog, change to palettes and select black, 20%;  next I click on options and select Postscript options, from there I select line and an angle and frequency.   This produces exactly the fine line shading I need, when I print it on my postscript printer.

The problem is that when I save the file as an .eps or .ai file to send to another prepress, the screen in their file always show up as dots not lines.  I have not been able to find a way around this, the other fill types use tiling and that does not produce the same consistent shading.