Plotted vector (ps, pdf, svg) files with 0-length lines pads dissapper.

I made a PCB layout copied in PDF and PS vector formats on demand of my client who typically uses CorelDraw and other software to make the photo-master for farther small series production. He reported that pads (actually vector shaped rings) on DIP-case disappeared except the rectangular one.
When actually same ring they were present on every other footprint was perfectly printed. After closer analysis I established that all the
I checked out myself all that files with 'InkScape' and 'evince' and found each pad perfectly present including the problem some, not as my client reported.
After closer inspection of footprints and and resulting PS file I established that the problem rings are actually not circular shapes but 0-length rounded lines, which not Linux libraries ignore when linux some process correctly.
Possibly it would be the best if during generating plot, 0-length lines (when width==height) to be replaced with circles, with the same thickness.