IIS certificate renewals 2048 rsa key

Hello,

When I use CSR mecanism to renew a certificate inside IIS, always IIS create a CSR with a 1024 public key length even if old certificate has a 2048 or 4096 public key length.

Is there a way to force IIS to have 2048 key length by default and not 1024 ? 
I checked on registry key or IIS option but find nothing specific.

I tried with IIS crypto to force 2048 but still create with 1024 length.

Thank you