USP Pro makes it easy to specify Custom Post Formats for submitted posts. This quick tutorial explains how to do it in one easy step.
To set a Custom Post Format for any form, just include the following line:
<input name="usp-custom-format" value="video" type="hidden" />
Replace “video” with the post format of your choice. Here is a list of available formats. Note that Custom Post Formats must be supported by your theme in order for this to work. See Adding Theme Support for more information.