Different priorities for different softirqs

Hi,

On https://rt.wiki.kernel.org/articles/r/t/_/RT_PREEMPT_HOWTO_6bc9.html I
noticed that there are different softirq kthreads for every softirq. So they
could be prioritized differently.
In my rt-patched kernels 3.2.11-rt20 and 3.0.24-rt42 I can only see one
ksoftirqd instance per cpu.

I did not find any hints in kernel/softirq.c where each of those kthreads is
generated. I only see ksoftirqd.

From RT_PREEMPT_HOWTO_6bc9.html:

...
2 ?        S      0:00 [softirq-high/0] 
3 ?        S      0:00 [softirq-timer/0] 
4 ?        S      0:00 [softirq-net-tx/] 
5 ?        S      0:00 [softirq-net-rx/] 
6 ?        S      0:00 [softirq-block/0] 
7 ?        S      0:00 [softirq-tasklet] 
8 ?        S      0:00 [softirq-hrtreal] 
9 ?        S      0:00 [softirq-hrtmono]
...

How can I get these softirq different threads? Did I miss a configuration
option?

Thanks
Christian