Ivy buildnumber not working

Ivy buildnumber not working

I am trying to get ivy:buildnumber working for my build's publish target
and am getting a bizarre error.
My publish target:
<target name="publish" depends="package">
<ivy:buildnumber resolver="default-resolver" organisation="myorg"
module="myapp" revision="0.2" />
<ivy:publish resolver="default-resolver"
pubrevision="${ivy.new.revision}" overwrite="true" update="true">
<artifacts pattern="gen/dist/pub/[artifact].[ext]" />
</ivy:publish>
</target>
The error I'm getting:
publish:
[ivy:buildnumber] :: loading settings :: url =
jar:file:/home/myuser/sandbox/dsi/workbench/eclipse/4.2/eclipse/plugins/org.apache.ivy.eclipse.ant_2.3.0.final_20130110142753/ivy.jar!/org/apache/ivy/core/settings/ivysettings.xml
BUILD FAILED
/home/myuser/sandbox/dsi/workbench/eclipse/workspace/myapp/build/build-core.xml:289:
Unknown resolver: default-resolver
The thing is, my Ivy settings file is not located at
org/apache/ivy/core/settings/ivysettings.xml. My Ivy settings file is
located at ~/ivy/ivy-settings.xml.
So I think somehow I'm not configuring ivy:buildnumber correctly, and so
it's defaulting to whatever Ivy settings file that Ivy ships with. And
since my default-resolver isn't defined in that shipped settings file, it
can't find a resolver to publish against.
Any ideas? Thanks in advance!