Missing shades when printing from plt file

Hi everyone

I have some dwg files with several lines and a few solid shades exported to .plt destinated to be printed in a plotter. Now I want to store these plt as pdf in a hard drive but when printing to pdf with the default options of pdfcreator most of the shades are missed.

I'm using abviewer7 to open plts and pdfcreator to print them but the shades do not appear properly.

I've tried almost everything in the options but nothing works.

When saving the file as tiff or jpg the shades are ok, but I really would like to have a pdf file.

I have had this problem for a long time, even when printing from autocad or corel, sometimes objects or colors are missed, but I cannot solve this.

This is the result of printing with pdf creator:

http://img21.imageshack.us/img21/9110/printedwithpdfcreator.jpg

And this is how the file should look like:

http://img62.imageshack.us/img62/867/exportedasjpg.jpg

 

Hope anyone could help, I'd be very thankful