SKF vector support

[henkdeleeuw]

I am looking for a solution to convert Autosketch .SKF files to another vector format.
I had found that XnView / XnConvert was able to read .SKF files and convert them to .PDF.
I have installed XnView MP on my Linux machine, and indeed, it can open my .SKF files, and show a thumbnail of the contents.
However, when I convert the files to PDF, the result is only the (bitmap) thumbnail, with a resolution where I cannot recognize any of the content.
When I open the .SKF files in Autosketch, the full resolution is present, so it is not true (as sometimes suggested) that .SKF files are thumbnail-only.
Is XnView / XnConvert able to convert the vector format in .SKF files to a vector format .PDF, or is it a bitmap-only program?
If it can convert vector format, then it can be useful to me, otherwise I will have to convert the files one by one with Autosketch itself.

[xnview]

XnView doens't support native vector format