When I create a web export of my pad that contains pages with umlauts in the name, the corresponding file names get the same name. This is not a problem as long as I am on my mac where I can open and read an exported pad without problems. When I pass the export on to a friend who uses Linux, then things just break down and links do not work.

Try naming a page something like "lök" (onion in Swedish), link to it from another page and then do an export and you will see what I mean.