Here\'s my appender configuration from my app.config. This just prints out the literal string instead of translating it to the date (i.e., it literally prints \"[START: %d
I encountered this problem and a quick workaround I used is to just use a fixed header and footer. Then do this as soon as you have the ILog object:
log.Info(string.Format("[START: {0} ]\r\n", dateString))
So just under the header you will get the information you desire.
E.g
===Start===
[START: 2012-02-23 12:12:12 ]
logs...