I've finally found a way to convert old format drawings of 1/2 VW conversion to any usable format like jpd / tiff. It's now printable!
1. Use original (.wmf) format files
2. Open with application JT2Go (free)
3. Print as pdf (Black&White / scale to fit / set for best quality / choose format A1 or B1) with application PDF24
4. In Acrobat Reader, save as .tiff file
5. Open in Application InfranView 64 and Replace colors Black-> White and White -> Black, then save without compression
6. Open with Paint and adjust select area to save as new file, then save as .jpg