HDWallet accounts keys with BITBOX

[kiltro]

Hi there,

I'm using BITBOX to construct a transaction that takes as input an address generated via account.getChainAddress(0) but I'm getting an error apparently because the keys don't match.

How could I get the keypair of the following address:

let parent = bitbox.HDNode.fromSeed(seedBuffer);
let child = bitbox.HDNode.deriveHardened(parent, index);
let account = bitbox.HDNode.createAccount([child]);
let address = account.getChainAddress(0);

Thank you guys.