CryptoAPI and 5 bytes exponent public keys

One customer of mine wanted to import a public key he got from a partner. That public key had a 2048 bits modulus and a 5 bytes exponent.The problem was that CryptoAPI's RSAPUBKEY structure doesn't allow a 5 bytes exponent because it defines the public exponent with a DWORD (4 bytes max): typedef struct _RSAPUBKEY {DWORD               magic ;DWORD               bitlen ;DWORD               pubexp