Important: if any of your affixes have a period in them, you refer to them replacing the period with an underscore. For example, 3s.S becomes 3s_S.
You generally refer to an affix using the clip element in your transfer rules. The part attribute of the clip element references an attribute usually and this attribute consists of potential tags which can be features or affix glosses.
If you are comparing a clip element to see if it matches an affix, you should use the literal tag element and write the gloss there. Remember the period-underscore substitution above.
