Porch step problems

[lgswe]

I have a 28' wide porch that is 14" above the ground across the front. I have 5 post going up to a beam spaced evenly across. I want to add a step across the entire front. when I place the stair and start to increase it's width the stair start screwing my post placement. How does one handle this? The stairs keeps trying to install a doorway all the way across the front of the porch thus changing the post placement. Am I missing a setting somewhere? Would I just be better off using p-solids for the step and move on? I like using the stairs encase I fudge around with the terrain later.