PS3 problem, need help (I know how to fix it, but need help still)

[mainman]

Well,

I have made a stupid mistake.

I got my PS3 hooked on an HD-tv, which supports 720p and 1080i.

I use HDMI and with custom settings (I pick wich resolutions my tv supports). Well, I was messing around with my PS3 settings.
Then I made a mistake. I selected HDMI and deselected 576p, 720p and 1080i, and selected 576p and 1080p. After doing this, my screen went blank.

As you all know, XMB is displayed in the highest resolution possible (in this case 1080p, and my screen doenst support that). So I needed to reset my PS3 (using PS3 to scart). After reset, when I select HDMI again, I get that 30 seconds thing. But when displaying the 30 seconds, it still gives me a blank picture over HDMI because it displays it in 1080p.

I also reset it in XMB, 'restore default settings', still the same problem.

I can solve this problem, but I need to navigate threw XMB blindly. When the 30 seconds thing happens, I must press 'yes' and then custom, and then deselect 1080p, so I will get a picture through HDMI.

After I get a picture, I can select the regular settings on my PS3.

So what I need is a walkthrough.

Example:
Press X in this screen, Press directional button in that screen, etc.

Help me please.