Support for Versioned Transaction

[alchemistgo87]

I want to add a new custom operation to the plugin but in that operation I need to use VersionedTransaction instead of the normal one.

I am able to do this inside the handler as follows:

import { Signer } from '@metaplex-foundation/js';
import { Signer as SolanaSigner } from '@solana/web3.js';
..

export const makeOfferOperationHandler: OperationHandler<MakeOfferOperation> = {
  async handle(
    operation: MakeOfferOperation,
    metaplex: Metaplex,
    scope: OperationScope
  ): Promise<MakeOfferOutput> {
    const builder = await makeOfferBuilder(metaplex, operation.input, scope);

    const { blockhash, lastValidBlockHeight } = await metaplex.connection.getLatestBlockhash();

    const lookupTableAccount = await metaplex.connection
      .getAddressLookupTable(operation.input.addressLookupTable)
      .then((res) => res.value);

    const messageV0 = new TransactionMessage({
      payerKey: builder.getFeePayer()!.publicKey,
      recentBlockhash: blockhash,
      instructions: builder.getInstructions(),
    }).compileToV0Message([lookupTableAccount!]);

    const transactionV0 = new VersionedTransaction(messageV0);

    transactionV0.sign(builder.getSigners() as SolanaSigner[]);

    const confirmOptions = makeConfirmOptionsFinalizedOnMainnet(metaplex, scope.confirmOptions);

    const signature = await metaplex.connection.sendRawTransaction(
      transactionV0.serialize(),
      confirmOptions
    );

    const response = await metaplex
      .rpc()
      .confirmTransaction(
        signature,
        { blockhash, lastValidBlockHeight },
        confirmOptions?.commitment
      );

    const output = {
      response,
      ...builder.getContext(),
    };

    scope.throwIfCanceled();

    return output;
  },
};

But getting this error while signing the transaction: Cannot read properties of undefined (reading 'slice')

(I know type-casting the Signer was a bad idea.) Does anybody know how to solve this issue?