This is actually very tricky as for fully support you need to be able to parse the full scope of the Excel formulas to ensure you offer only text for translation.
Till Microsoft offers some easier way, I would say this is not doable in some robust manner.
Not sure if that would be desirable. How would you guarantee that formulas don't get modified - accidentally or even intentionally - and the results are incorrect? Can you give a scenario that justifies modifying a formula during translation?
Translate
