I think your column would fall under the (GS) category of Overhead. So you need to set your columns' Floor Plan Display to Overhead All, and set the Overhead linetype parameter to a linetype that will show as dashed given it's size. Something like Hidden may get you close.
Edit: Unless you are referring to the pad footing, in which case you have found one of the biggest downfalls with profiles, there is no setting for Projected Lines! So you'll probably have to workaround it using the Overhead Setting.
Isn't it a shame that the profile for a column is only a plan profile, not a section profile? If we had the option to create a section profile there'd be no need to create two separate columns! Wishful thinking....
Cheers,
Link.