can't add custom SBT action - sbt

Question

I just got started with SBT.
To add a custom action, I made a following task and add that .scala file to 'project' folder as SBT wiki guides.
//MyProject.scala
import sbt._
class HelloWorldProject(info: ProjectInfo) extends DefaultProject(info)
{
lazy val hi = task { println("Hello World"); None }
}
after adding the scala src file for configuration, layout of the project folder look like this.
/development/scala/SomeScalaProject/
|~lib/
|~project/
| |~boot/
| | |~scala-2.7.7/
| | | |~lib/
| | | | |-scala-compiler.jar [RO]
| | | | `-scala-library.jar [RO]
| | | `~org.scala-tools.sbt/
| | | `~sbt/
| | | `+0.7.4/
| | |~scala-2.8.1/
| | | `~lib/
| | | |-scala-compiler.jar [RO]
| | | `-scala-library.jar [RO]
| | `-sbt.boot.lock
| |-build.properties
| |
| `-MyProject.scala //here
|
|+src/
But even after 'reload' or 'update', running the hi task in SBT is not available at all. what am i missing?
D:\development\scala\SBEStudy>java -Xmx512M -jar "D:\development\.common\sbt-la
nch-0.7.4.jar" update
[info] Building project SomeScalaProject 1.0 against Scala 2.8.1
[info] using sbt.DefaultProject with sbt 0.7.4 and Scala 2.7.7
[info]
[info] == update ==
[warn] No dependency configuration found, using defaults.
[info] :: retrieving :: nephilim.practice#scalabyexample_2.8.1 [sync]
[info] confs: [default]
[info] 0 artifacts copied, 0 already retrieved (0kB/391ms)
[info] == update ==
[success] Successful.
[info]
[info] Total time: 1 s, completed 2010. 12. 8 오후 7:14:39
[info]
[info] Total session time: 2 s, completed 2010. 12. 8 오후 7:14:39
[success] Build completed successfully.
> reload
[info] Building project SomeScalaProject 1.0 against Scala 2.8.1
[info] using sbt.DefaultProject with sbt 0.7.4 and Scala 2.7.7
> hi
[error] No action named 'hi' exists.
[info] Execute 'help' for a list of commands or 'actions' for a list of availab
e project actions and methods.

Answer 1

It was my mistake. :(
"MyProject.scala" should be located under /project/build directory instead of /project directory.