kernel configuration problem

Hi to all!
I have recently compiled the 2.6.6 kernel..i run a debian linux (not really a distro as i built it on my own).. The kernel i use now is a 2.4.26. The problem is that when i do make menu-config on my new kernel and even if i do everything well (i am not totally ure about that but that is what i think!) the 2.6.6 will not recognize the /dev/ttyS0 and /dev/ttyS1..etc (the serial ports where i have my modem plugged in).On the 2.4.26 everything is fine though...i have compared many times the two configurations asked for help from friends but i cannot find the solution...can anybody tell me if i can do sth in order for the kernel to find those ports when booting? Is there a way to 'force' the computer to query those serial ports?
I also have to say that the /dev/ttyS0..etc exist but when trying to select them it says 'access denied'