Communications cable between two computers issue

Hey all,
OK, here's my problem. I have a dial up connection set up for a null modem
(communications cable between two computers). Now, when I go into the dial
up connection properties and configure "Communications cable between two
computers (COM1)" it refuses to save my changes. I'll set the maximum speed
to 2400 then click ok twice to return to the network connections screen, then
I'll go back in to check the setting and it will have reverted to what it was
before. In XP, configuring this setting is not an issue at all...it will
keep the settings I change it to, so I know it's something that I'm allowed
to change. Another weird thing is that yesterday it was set to 19200 bps and
today when I got into work it was somehow set to 9600. Is this a bug???