Calling an ant script from within a .nsi file

[Irish2007]

I am trying to run an ant script from within the installer and it is not running properly.

I tried both of the following commands:
Execwait '"$INSTDIR\ant" -f "$INSTDIR\build.xml"'

nsExec::Exec '"$INSTDIR\ant" -f "$INSTDIR\build.xml"'

After the nsExec command I did a Pop $0 and got "error" - is there a way to actually get the error that was produced by the code? (I even tried $1 and $2...)

I can run the ant script from the command prompt without error, so there must be something wrong with my commands... this is my first project with NSIS.

I'm running this on Windows XP, using NSIS version 2.30

Thanks!