Loss of Opacity when export drawing to PDF

When I ‘export drawing to PDF’ from Toon Boom Studio 5.0 (Build 5.1.13834) the opacity is lost on the PDF. When I then open the PDF in Adobe Illustrator I get the PDF Warning ‘The document contains PDF objects that have been reinterpreted: An unknown shading type was encountered’. The appearance of the element now has an opacity of 100%. I am working on Mac OS X v 10.6.8. Is there any way to preserve the opacity information during the first export to PDF from Toon Boom. Presently I have to just correct the opacity manually, but this is not possible where there are multiple ‘layers’ on the original drawing as I can’t seem to select the layers behind and the breakdown of the image has too many elements to do them all individually from the layers menu in Illustrator. For complicated drawings, it’s a nightmare! Thanks

Have you tried Millions of colors + in the Options drop down list?
You can find the option by doing the export to image sequence, selecting Photoshop as the Format and then clicking on Options.

Thanks for the reply. I tried your suggestion but when i import the PSD into Illustrator the image is rasterised, but i want to keep it vector to edit. Using the PDF was the recommendation I was given to preserve this.