With all of the options there are for importing igs, step and parasolid parts into Inventor, there are no options to select which template shuold be used once this part is imported. Quite often a user will have different tempaltes depending on the operation or units being used. There should be an addition under the open dislog to allow a user to select which template they would like to use. Whether it is a custom one or the default out of the box. Just give us the freedom to select.
See this thread.
http://forums.autodesk.com/t5/Autodesk-Inventor/Imported-Part-Template/td-p/4352426