I know we can use easy populate to export catalog info, but I am wondering how can I export my customers and orders info into a csv file? I do need this info for my accounting software

I am also interested in this. My database has something wrong so I want to manually import orders and customer to my new B2B store but I dont want to make the upgrade option. I tried it before and got the same problems as before so I need to make a "clean" install.

OK I now know that you have to export/import Tables. Using PHP My Admin will make your task easier and your life happier. It is very very simple I dont even think it needs explanation, just get into PHPMyAdmin and go into your old database. See all tables you will notice some of them begin with "orders_*" you have to export all of them, one by one. then import them in the new one. its Easy. then go with "customers_*" tables its the same. Basically check the name of the tables you would like to import.
Dont forget to import Address_book table.

All this should be exported as the default format of SQL, no CSV. Save the files in a TXT file name it as the table you are exporting.

Now remember Products and Categories if changing from CE to B2B is not EPA or EPB compatible.... You will also have to do this manually... but tables have some bugs I have found with languages if you have at least two of them installed... I dont know how or why but some of them wont be able to be changed in your new install (6.4 B2B at least). I found so,e post of people having this same problem. In this case you will have to do this manually in the mySQL Tables or you will have to create them again (you may use EPA).