you should create a new key pair and install it with sn:
C:\>sn
Microsoft (R) .NET Framework Strong Name Utility Version 4.0.30319.0
Copyright (c) Microsoft Corporation. All rights reserved.
Usage: sn [-q|-quiet] <option> [<parameters>]
Options:
..
-i <infile> <container>
Install key pair from <infile> into a key container named <container>.
-k [<keysize>] <outfile>
Generate a new key pair of the specified size and write it into <outfile>.