conscript plugin fails to run sbt on Windows XP

[hsn10]

[trace] Stack trace suppressed: run last *:cs-run for the full output.
error java.io.IOException: Cannot run program "sbt": CreateProcess
error=2, SystÚm nem??e nalÚzt uvedenř soubo
[error] Total time: 0 s, completed 20.5.2013 18:21:58

for some unknown reason executing sbt on windows fails, but sbt.bat works fine. I can confirm this in groovy console:

groovy:000> new ProcessBuilder("sbt").start();
ERROR java.io.IOException:
Cannot run program "sbt": CreateProcess error=2, SystÚm nem??e nalÚzt uvedenř so
ubo
at java_lang_ProcessBuilder$start.call (Unknown Source)
at groovysh_evaluate.run (groovysh_evaluate:2)
...
groovy:000> new ProcessBuilder("sbt.bat").start();
===> java.lang.ProcessImpl@ec078b
groovy:000>

PROPOSED FIX: if plugin detect that it runs on windows, it should execute sbt.bat, not sbt