Interfacing custom module with Nios II

And if I was to change DATA_WIDTH to 32 bits, and my module declaration of Key is 128 bits, how do I instantiate it?

For e.g.

With DATA_WIDTH set to 128 I can put this in the slave.v

// Clock Key PlainText Load Reset CipherText Done

AES_128_EncryptionCore u0(clk,user_dataout_0,user_dataout_1,user_dataout_2,reset,user_datain_0,user_datain_1);

However if I set DATA_WIDTH to 32 surely I cant pass the Key input, or is there a way to concatenate?

OR would I have to edit my actual custom logic and have 4 x 32 bit key inputs?