I am not sure that is possible, but I have a work around which I use to fix buggy 3rd party extensions:
Create a new module
A very simple one, only 2 files are required.
app/etc/modules/Namespace_Fixer.xml
:
<?xml version="1.0"?>
<config>
<modules>
<Namespace_Fixer>
<active>true</active>
<codePool>local</codePool>
<depends>
<Broken_Module/>
</depends>
</Namespace_Fixer>
</modules>
</config>
Note the depends, this is very important so that it is loaded after.
app/code/local/Namespace/Fixer/etc/config.xml
:
<?xml version="1.0"?>
<config>
<modules>
<Namespace_Fixer>
<version>0.1.0</version>
</Namespace_Fixer>
</modules>
<global>
</global>
<frontend>
<layout>
<updates>
<broken_module> <!-- update this -->
<file>namespace/module_fixed.xml</file>
</broken_module>
</updates>
</layout>
</frontend>
</config>
Override the layout file to point to our new one.
Duplicate the layout XML
You want to point at the new XML, in there you can do the right thing and add a name
to the block and call it where ever you want.