Make sure you are licensed to reverse-engineer assemblies to as a strong name. I do not want you to have any legal troubles. You can strong name the assembly using the ILDASM and ILASM commands. In a Visual Studio command prompt.
Use the ILDASM to convert the assembly into MISL code.
ILDASM MyThirdParty.dll /out:MyThirdParty.il
Use ILASM to compile with a strongname key.
ILASM MyThirdParty.il /dll /resource=MyThirdParty.res /key=MyKey.snk
If you need to make a strong name key use the SN command. I think its the -k option.
If you get a BadImage exception then you check what CLR version the assembly was compiled in. If its a CLR 2.0/3.5 then use "C:\Windows\Microsoft.NET\Framework\v2.0.50727\ILASM" instead of the 4.0 version.