sbt is using "default" project instead of creating a new one

I've just installed sbt on my Windows Vista machine, following the guide on github wiki, using a sbt.bat script containing

set SCRIPT_DIR=%~dp0
java -Dfile.encoding=UTF8 -Xmx1024M -Xss1M -XX:+CMSClassUnloadingEnabled 
     -XX:MaxPermSize=256m -jar "%SCRIPT_DIR%sbt-launch.jar" %*

When I run sbt in an empty directory, I get

L:\foo>sbt

L:\foo>set SCRIPT_DIR=L:\lib\sbt\

L:\foo>java -Dfile.encoding开发者_运维问答=UTF8 -Xmx1024M -Xss1M -XX:+CMSClassUnloadingEnabled
-XX:MaxPermSize=256m -jar "L:\lib\sbt\sbt-launch.jar"
[info] Set current project to default-058262 (in build file:/L:/foo/)
>

instead of expected prompt to create a new project. What am I doing wrong?

In contrast with SBT 0.7, SBT 0.10+ does not prompt you for project creation, but assumes some default configuration and deploy its own working directories.

If you want to provide you settings, you must add an build.sbt file or a full configuration.

Add the np plugin. This replaces the previous functionality. https://github.com/softprops/np