I went to Snowsled website, but could find no mention of clothing. Not even a list of what they stock. All I could find were articles on thier sledges.
Could you post the URL of the site you bought the smock from. Here's the link I went to.
Forgive me if I'm just being stupid, but I found thier site unhelpful at best.
http://www.snowsled.com/html/frame_journeys.html