Task Calendar Trouble

flagz 

Nobody seems to have picked-up your question and it made me re-think about what you actually are asking for. Why bother randomising? It just makes it complicated. All task must be performed with the same frequency during a given year. Or am I wrong? The easiest would be to just start with Task1 the first working day of the year, Task 2 on the second day and so on. If you hadn't thought about that yourself yet, the attached workbook gives a very quick and dirty solution.

I assumed that Saturdays and Sundays are not working days. If incorrect, you can adjust the "x" marks yourself. Or perhaps you need to exclude more working days to account for public holidays. Play around with the filter buttons to create a display that suits you best.