This can be done by altering the config file and using the <codebase/> node:
<configuration>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="myAssembly"
publicKeyToken="32ab4ba45e0a69a1"
culture="neutral" />
<codeBase version="2.0.0.0"
href="
http://www.litwareinc.com/myAssembly.dll"/>
</dependentAssembly>
</assemblyBinding>
</runtime>
</configuration>
For the runtime to use the <codeBase> setting in a machine configuration
file or publisher policy file, the file must also redirect the assembly
version. Application configuration files can have a codebase setting without
redirecting the assembly version. After determining which assembly version
to use, the runtime applies the codebase setting from the file that
determines the version. If no codebase is indicated, the runtime probes for
the assembly in the usual way.
If the assembly has a strong name, the codebase setting can be anywhere on
the local intranet or the Internet. If the assembly is a private assembly,
the codebase setting must be a path relative to the application's directory.
For assemblies without a strong name, version is ignored and the loader uses
the first appearance of <codebase> inside <dependentAssembly>. If there is
an entry in the application configuration file that redirects binding to
another assembly, the redirection will take precedence even if the assembly
version doesn't match the binding request.
Source: MSDN
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpgenref/html/gngrfcodebase.asp