Caveat: I haven't actually used log4net. But if I understand correctly, the configuration is an XML file, isn't it? And the pattern is just text with some special tokens. So have you tried embedding actual tab characters in your pattern? The XML sequence for a tab is 	
, e.g.:
<conversionPattern value="%utcdate	[%thread]	%-5level	%logger	%message%newline" />
Or if you're supplying the pattern some other way (perhaps via the PatternString
constructor or whatever), just include tab characters in the string you're passing in. The docs for that constructor defer to the PatternLayout
docs to talk about the string itself, and there they say:
You are free to insert any literal text within the conversion pattern.
(Their emphasis.) Worth a try, anyway...