How can i create a token ERC20 with a customized function

Your code fragment has a _Token variable, which you're treating as a generic address (using call() on it). If you know that this address is an ERC20 token, you can use Solidity to cast that variable to the appropriate type, and then it's a more intuitive function call, rather than figuring out signature hashes:

contract ERC20Token {
  function transferFrom(address from, address to, uint value);
}

contract MyContract {
  function myFunction(address tokenAddr) {
    ERC20Token tok = ERC20Token(tokenAddr);
    tok.transferFrom(_owner, _recipient, 100);
  }
}

This sort of transfer can be done in two stages.

The person who aspires to be good needs to first call vbToken.approve(<your contract's address>, 5) (or rather 5 * 10**decimals). This authorizes your contract to take 5 vbcoins from them.

They then call sendVBCoins(5) (or, again, more likely 5 * 10**decimals). Inside sendVBCoins, you will call vbToken.transferFrom(msg.sender, _howmuch). If that succeeds, then you've received those vbcoins from them, and you can consider them to be a "good person."