Hi Mike,
If I understand your question correctly, you can achieve this by applying the 'translucency' setting for the boundary layer. This can be applied by double-clicking on the layer in the Explorer Window > this will bring up the Layer Properties dialog box > under 'Enhanced Rendering' > Translucency either drag the slide button/type a number/click on the up/down arrows to change the level of translucency
You can click on the 'Preview' button to review the outcome of this setting. Once you are happy with the results, click on OK to apply
screenshot below illustrates the Layer Properties dialog box and translucency setting
![ScreenHunter 231]()
Create a PDF as per usual and the translucency should be carried across into the PDF.
Hope this helps!