Problem during recording on LE 5, reverse latttency?

Hi there, i’m using windows 7 64bits home premium, my sound card is a lexicon alpha, and i’m recording on cubase LE 5. The problem is: when i record guitars over a bass, drums, audio files, on my headphones i hear no lattency, but when i playback the guitar play a little earlier than it should, and when i go to device configuration and configure the audio buffer to the lattency side (opposite to high stability) on my lexicon alpha controls… when i get back i have no sound at all, no recording, no playback, so i have to switch it back to were it was.
Anyone have an idea on how can i solve this problem? Thanks in advance

Try to selct no driver then switch the latency and then activate the lexicon driver again
or close cubase change latnecy and start again. With my maudio FastTrackPro i couldn^t switch as long soundinterface was used.

greetz Bassbase