Figured Bass slash question

I'm coming to this example. When I input the slash such as the penultimate note F at measure 1, it can't be exported correctly. I read from the manual that the slash can only be correctly displayed with the number 5. But here as the picture shows (if I'm correct), it's only a single slash. I have to enter a 5 to correctly export it in Musicxml. How can I do this as the original?

Haipeng