As far as i know , BizTalk is not the general tool for generating XML from a CSV file. You would have to search for some other tool or software that does that.
XML in BizTalk is used to represent Schemas, internal data representations and other data that would be needed during integration of one system/applicaiton with another.
If you want to use the csv file as input data to your BizTalk project than you have to write a schema that would represent that csv file. Then generate an instance of that schema (Which would be in xml format), where you can input the values you need.
To Generate a schema file in BizTalk just add new item and select "Schema" from the existing templates and you get a graphical designer where you can design the schema.
Hope this helps,