I am not entirely sure if I understand your question, but there is a data log checkbox in signaltap. When checked, it will log your signaltap data in your PC when it is triggered.
The log will contain the date/time of the sample. To recall a previous event, just double click on the desired event in the log and the data will be presented to you. (I use this feature when I need to find an event that does not directly correlate to my trigger while using continuous trigger mode)
Hope this helps.
