asString() output for cron containing weekdays

Hi,

First of all thanks very much for this library. Only recently discovered it but it is extremely useful for us while moving away from a certain scheduler and replacing it with another one.

Our expressions typically contain written weekdays such as MON, TUE, etc. Parsing that up works great, but I can not find a way to get the output as such when building a CRON and getting the expression. (Cron#asString) It always seems to output integer values for the weekdays, which unfortunately, we can't deal with in our legacy solution.

Any idea / hints on how to get named weekdays instead of integers?

Thanks very much!