SWV not working with STM32F469I-DISCO

I'm using a 32F469IDISCOVERY board (Cortex-M4). The integrated ST-Link V2-1 has firmware V2J37M27 and is configured as "Debug + Mass storage + VCP Modus" (default). It doesn't look like it has a jumper or solder bridge to connect SWO and I think it's permanently connected to ST-Link.

I create an new empty project in STM32CubeIDE v1.6.1

• File -> New -> STM32 Project
• Board Selector -> STM32F469I-DISCO -> Next
•  Project Name: swv_foo1, Language: C, Binary Type: Executable, Project Type STM32Cube -> Next
•  Firmware Package STM32Cube FW_F4 V1.26.1 -> Finish
•  Initialize all peripherals with their default Mode? -> No
•  Clock Tree shows SYSCLK is HSI -> 16MHz
•  change PB3 to SYS_JTDO-SWO
•  change SYS Debug: "Trace Asynchronous Sw"
•  Save .ioc -> Generate Code -> YES
•  Add busy loop to main.c

void Delay (__IO uint32_t nCount)
 {
 while (nCount--)
 {
 }
 }

 and call it in the endless loop, toggle orange LED:

while (1)
 {
 /* USER CODE END WHILE */
 HAL_GPIO_TogglePin (LED2_GPIO_Port, LED2_Pin);
 ITM_SendChar ('x');
 Delay (1000000L);
 /* USER CODE BEGIN 3 */
 }

•  Project -> Build Project (finished without errors or warning)
•  Run -> Debug Configurations -> STM32 Corex-M C/C++ Application -> New launch configuration
•  Debugger -> ST-LINK (ST-LINK GDB server)
•  Serial Wire Viewer (SWV)

[x] Enable
 Core Clock 16MHz
 SWO Clock: 2000 kHz
 Port number: 61235
 [x] Wait for sync packet

•  Apply -> Debug
•   Download and Verifying, Debugger stopps in main at HAL_Init ()

 Tab "SWV ITM Data Console"

   Configure Trace:

     Timestamps

       [x] Enable Prescaler 1

     ITM Stimulus Ports

       [x] 0

     -> Ok

   Port 0 shows up

   -> red filled "record" circle (Start Trace)

 F8 (Resume)

 Orange LED (LED2) starts to blink but

 SWV Trace Log, SWV ITM Data Console, SWV Statistical Profiling keeps empty.

 I've checked DGBMCU_CR and it's 0xe0042004 so

 TRACE_IOEN = 1

 TRACE_MODE = 00: TRACE pin assignment for Asynchronous Mode

 chapter 37.14.2 of the STM32F469xx reference manual says

 0xC5ACCE55 has to be written @E0000FB0 but I'm unsure if this shouldn't be done from the debugger.

 dm00354244-stm32-microcontroller-debug-toolbox-stmicroelectronics.pdf

 doesn't even mention it but I also tried

   volatile uint32_t *ITM_LAR = (volatile uint32_t *)0xE0000FB0; // ITM->LAR

   *ITM_LAR = 0xC5ACCE55; // Enable Access

 but this doesn't change anything.

 I'm really running out of ideas here. Can someone help me?

Thank you, Andy