Perhaps you could use a query to calculate the count of weekdays. Something like:
SELECT Count(YourTableName.FieldNameToCount) AS NumOfWDays
FROM YourTableName
WHERE (((YourTableName.YourDateFieldName) Between [Start Date] And Date()) AND ((Weekday([YourDateFieldName]))<>1 And...
Not sure that "MUST" is quite right. I thought that expressions without them would still work if the field name had NO spaces in it. I would agree that they are advisable though.