How to deal with 'fifth tone' creating entries

I can’t seem to find a good way to deal with ‘fifth tone’ when constructing custom phrases in my lists. The logical ones of putting no tone number or using the number 5 do not seem to work or generate error messages.
Is there an accepted way of doing this? Or do I need to anticipate the tone from context?

Using 5 to indicate a neutral tone should work! For example “shen2me5”. Would you be able to paste any error messages you’re running into (along with what reading you’re typing for the reading)?