build.xml

<?xml version="1.0"?>
<project xmlns:ivy="antlib:org.apache.ivy.ant" default="all">
        <target name="all" depends="clean,mirror-upstream"/>
        <target name="clean">
                <delete dir="${basedir}/cache"/>
                <delete dir="${basedir}/out"/>
        </target>
        <target name="mirror-upstream">
                <ivy:settings file="ivysettings.xml"/>
                <ivy:install organisation="aopalliance" module="aopalliance" revision="1.0.0" from="ibiblio" to="thirdparty-sink-fs"/>
        </target>
</project>

ivysettings.xml

<ivysettings>
        <resolvers>
                <ibiblio m2compatible="true" name="ibiblio" namespace="maven"/>
                <filesystem name="thirdparty-sink-fs">
                        <ivy pattern="${basedir}/out/[organisation]/[module]/ivy-[revision].xml" />
                        <artifact pattern="${basedir}/out/[organisation]/[module]/[organisation]--[module]--[artifact]--[type]--[revision](--[classifier]).[ext]" />
                </filesystem>
        </resolvers>
        <namespaces>
                <namespace name="maven">
                        <rule>
                                <fromsystem>
                                        <src org="aopalliance" module="aopalliance" rev="1.0.0"/>
                                        <dest org="aopalliance" module="aopalliance" rev="1.0"/>
                                </fromsystem>
                                <tosystem>
                                        <src org="aopalliance" module="aopalliance" rev="1.0"/>
                                        <dest org="aopalliance" module="aopalliance" rev="1.0.0"/>
                                </tosystem>
                        </rule>
                </namespace>
        </namespaces>
        <caches defaultCacheDir="${basedir}/cache"/>
</ivysettings>

output.txt

$ ant
Buildfile: /home/duffy/tmp/build.xml

clean:

mirror-upstream:
[ivy:install] :: Apache Ivy 2.4.0-local-20130613103924 - 20130613103924 :: http://ant.apache.org/ivy/ ::
[ivy:install] :: loading settings :: file = /home/duffy/tmp/ivysettings.xml
[ivy:install] :: installing aopalliance#aopalliance;1.0.0 ::
[ivy:install] :: resolving dependencies ::
[ivy:install] :: downloading artifacts to cache ::
[ivy:install] :: installing in thirdparty-sink-fs ::
[ivy:install] :: install resolution report ::
[ivy:install] :: resolution report :: resolve 0ms :: artifacts dl 0ms
        ---------------------------------------------------------------------
        |                  |            modules            ||   artifacts   |
        |       conf       | number| search|dwnlded|evicted|| number|dwnlded|
        ---------------------------------------------------------------------
        |      default     |   1   |   0   |   0   |   0   ||   0   |   0   |
        ---------------------------------------------------------------------
[ivy:install] 
[ivy:install] :: problems summary ::
[ivy:install] :::: WARNINGS
[ivy:install]           ::::::::::::::::::::::::::::::::::::::::::::::
[ivy:install]           ::          UNRESOLVED DEPENDENCIES         ::
[ivy:install]           ::::::::::::::::::::::::::::::::::::::::::::::
[ivy:install]           :: aopalliance#aopalliance;1.0.0: java.text.ParseException: inconsistent module descriptor file found in 'http://repo1.maven.org/maven2/aopalliance/aopalliance/1.0/aopalliance-1.0.pom': bad revision: expected='1.0' found='1.0.0'; 
[ivy:install]           ::::::::::::::::::::::::::::::::::::::::::::::
[ivy:install] :::: ERRORS
[ivy:install]           ibiblio: bad revision found in http://repo1.maven.org/maven2/aopalliance/aopalliance/1.0/aopalliance-1.0.pom: expected='1.0 found='1.0.0'
[ivy:install] 
[ivy:install] :: USE VERBOSE OR DEBUG MESSAGE LEVEL FOR MORE DETAILS

BUILD FAILED
/home/duffy/tmp/build.xml:10: Problem happened while installing modules - see output for details

Total time: 0 seconds