Here is how I did it.
1. Pick the player you want in a util position
2. When looking at your roster page, right click on the link and copy the address bar, it will look something like this
http://whatifsports.com/mlb-l/themewiz_buildteam.asp?action=add&spot=9&playerid=2194466
the 2194466 is the unique player id (1894 hugh duffy) and the "add&spot=9" is the position on the roster of the player (the first utility spot. C will be 1, 1b will be 2, 2b 3 and so on)
3. delete player from your roster
4. Paste the link, that you had already cut in step 2, into your toolbar
5. Where is says "add&spot=9" change 9 to what position on the roster you want him to occupy. (1=C, 2=1b, 3=2b, 4=3b, 5=ss. 6,7,8=of....)
6. Type enter
7. Player should now be there. Rinse and repeat.