Microsoft Visio Start/End dates

I have a ton of problems with Visio 2007.

I’m trying to draw a Gantt Chart.

The program wont let me add dates that fall on a Saturday and Sunday, and mess them up intentionally, and I can not stop Microsoft from acting smart and messing up the dates.

>>> nvm. its in the working dates. fixed.

Then, Actual Start and Actual End fields may not be left blank.

>>> i used a work around by adding “User Defined Text”. but it would be nice if somebody told me how to do it properly.

Can anyone please help me solve these problems?