If you want to convert a SWMM5 model (*.inp) file into corresponding shape files, and viceversa, you can try a conversion tool at
http://www.lago-consulting.com/swmm5_to_shp.html
There was a previous thread (thread162-163105) asking for that conversion.
In case that somebody is interested, there is a new conversion tool for that on
http://www.lago-consulting.com/hec-rastomike11.html