InfoPath Dev

I created an InfoPath form (.xsn) and published it to an already existing Forms Library. When I do a 'New' in the forms library, the form template pops up. There are a couple of things I don't understand about this.

1. The form that pops up appears to be an .xml file but not an .xsn file. How is it that I publish an .xsn file but SharePoint shows it as an .xml file? I know an xsn file 'is' an xml file but still, why has the extension changed?
2. When I do a 'New', fill in the data, then Submit, it will submit the form to the libary, but always with the same name. Then when I get ready to close the form, it wants to know if I want to save it to the library. So, what should really happen here? I would think I would need to just save it to the form but I guess the submit does the posting of the data. If it is going to automatically submit the form, how can you make it have a unique name?

The xsn is the template that you design that allows you to create individual xml files.

You probably configured your SharePoint submit incorrectly. The data connection wizard asks you to specify a file name, but what happens if you specify a static name? You get files submitted always with the same name. You need to come up with a function that generates unique names based on your form's content. You should also read this: http://www.infopathdev.com/forums/t/12755.aspx

You can configure close behavior for your form, i.e. should it close after submit, should it prompt users to save, etc. Find these options in Tools > Form Options and in your submit button.