[vdr] feeds

[Leo Márquez]

Hi,
I'm trying to tune fta(free to air) feeds with VDR. Feeds are temporaly 
channels for an event that usually have low freqüencies.
To tune them I try to add or edit channels in my list. But I only know 
this for example:

30W (hispasat)
frequency: 11538
polarization: H
sr 6100

Some of this feeds are in 422 format. I have a nexus-s dvb-s FF card.
My question is if there is a method to force the pid update of a channel 
because I don't know this data.
I know the update names and pid option of the dvb card configuration but 
I don't know exactly how works. It seems that I have to wait VDR to 
update all channels.

Thanks.