Classical guitar notation

A lot of guitar music I look at has something like this* squiggly arrow (below) to mark the direction of a strum. I've seen suggestions elsewhere that we should use bow up/down marks (and I guess if there's no choice...) but i would prefer to implement the composer's autograph, if possible.

Can this be done as Musescore exists now? Or would it need to be a request? (and then my follow up question would be - how hard is it for me to create something like this and add it to a palette?)