code: func (r Network_Storage_Iscsi) EditCredential(username *string, newPassword *string) (resp bool, err error) {
  	params := []interface{}{
  		username,
  		newPassword,
  	}
  	err = r.Session.DoRequest("SoftLayer_Network_Storage_Iscsi", "editCredential", params, &r.Options, &resp)
  	return
  }
docs: // This method will change the password of a credential created using the 'addNewCredential' method. If the credential exists on multiple storage volumes it will change for those volumes as well.