I am not an expert in XAUI. But, I am aware that there is a section in Stratix II GX handbook that describes link Synchronization in XAUI mode. Please, review "Synchronization ||k|| (Word Aligner)" section on page 2-171 of the recent version (October, 2007) of the device handbook. It states, that four K28.5 control characters are required. You also need /A/ characters for Lane Deskew. Figure 2-124 should be helpful. It further references to Clause 48 of IEEE P802.3ae. I think, the key is to understand the whole synchronization flow. I hope, it helps.