+  # start transaction (post + history + (optional) banktrans)
+  SL::DB->client->with_transaction(sub {
+
+    if ((my $errno = GL->post_transaction(\%myconfig, \%$form)) <= -1) {
+      $errno *= -1;
+      my @err;
+      $err[1] = $locale->text('Cannot have a value in both Debit and Credit!');
+      $err[2] = $locale->text('Debit and credit out of balance!');
+      $err[3] = $locale->text('Cannot post a transaction without a value!');
+
+      die $err[$errno];
+    }
+    # saving the history
+    if(!exists $form->{addition} && $form->{id} ne "") {
+      $form->{snumbers} = qq|gltransaction_| . $form->{id};
+      $form->{addition} = "POSTED";
+      $form->{what_done} = "gl transaction";
+      $form->save_history;
+    }
+
+    # Case BankTransaction: update RecordLink and BankTransaction
+    if ($form->{callback} =~ /BankTransaction/ && $form->{bt_id}) {
+      # set invoice_amount - we only rely on bt_id in form, do all other stuff ui independent
+      # die if we have a unlogic or NYI case and abort the whole transaction
+      my ($bt, $chart_id, $payment);
+      require SL::DB::Manager::BankTransaction;
+
+      $bt = SL::DB::Manager::BankTransaction->find_by(id => $::form->{bt_id});
+      die "No bank transaction found" unless $bt;
+
+      $chart_id = SL::DB::Manager::BankAccount->find_by(id => $bt->local_bank_account_id)->chart_id;
+      die "no chart id:" unless $chart_id;
+
+      $payment = SL::DB::Manager::AccTransaction->get_all(where => [ trans_id => $::form->{id},
+                                                                     chart_link => { like => '%_paid%' },
+                                                                     chart_id => $chart_id                  ]);
+      die "guru meditation error: Can only assign amount to one bank account booking" if scalar @{ $payment } > 1;
+
+      # credit/debit * -1 matches the sign for bt.amount and bt.invoice_amount
+
+      die "Can only assign the full (partial) bank amount to a single general ledger booking" . $bt->not_assigned_amount . " " .  ($payment->[0]->amount * -1)
+        unless (abs($bt->not_assigned_amount - ($payment->[0]->amount * -1)) < 0.001);
+
+      $bt->update_attributes(invoice_amount => $bt->invoice_amount + ($payment->[0]->amount * -1));
+
+      # create record_link
+      my %props = (
+        from_table => 'bank_transactions',
+        from_id    => $::form->{bt_id},
+        to_table   => 'gl',
+        to_id      => $::form->{id},
+      );
+      SL::DB::RecordLink->new(%props)->save;
+      # and tighten holy acc_trans_id for this bank_transaction
+      my  %props_acc = (
+        acc_trans_id        => $payment->[0]->acc_trans_id,
+        bank_transaction_id => $bt->id,
+        gl_id               => $payment->[0]->trans_id,
+      );
+      my $bta = SL::DB::BankTransactionAccTrans->new(%props_acc);
+      $bta->save;
+
+    }
+    1;
+  }) or do { die SL::DB->client->error };