You should be able to put the "objmap.MapStyle = geoMapStyleRoad" at the top of your code sample. Not sure how you could stop the pushpins from being drawn as the defaut pushpin for the dataset before your custom pushpin but you could lock the form or control from being redrawn or updated until the import is complete.
Here is a link I gave to someone that was trying suspend the redraw of the map.
http://www.mp2kmag.com/mappoint/disc...pic.asp?t=3377