I came across another problem with the syntax highlighting in BlogEngine.Net. Whenever I used code blocks like so:
[ code:c#]
//some c# code
[ /code]
the formatting tags would be included in the output:

I
fixed this in CodeFormatter.cs by modifying the regular expressions that are used
to remove the formatting tags. I'm definitely not a regular expression
guru but all I did was allow the expression to match extra 'nbsp;' and
'<br />' elements that may be inserted after the [ code:c#] tags.
Both of the expressions below are the result after replacing all occurences of (\s|) with (\s| |<br />)*:
#region RegEx
...
private Regex codeBeginTagRegex = new Regex(
@"(<p>\r\n<div class=""code"">\n\[code:.*?\](\s| |<br />)*\r\n</p>\r\n|"
+ @"<p>\r\n<div
class=""code"">\n\[code:.*?\](\s| |<br />)*<br
/><br /><br />)",
...
private Regex codeEndTagRegex = new Regex(
@"(<p>\r\n\[/code\]</div>(\s|)\r\n</p>\r\n|<br
/><br /><br
/>\[/code\]</div>(\s|)\r\n</p>\r\n)",
...
#endregion
[/code]
This seems to work in most cases however the
tags have popped up a couple of times but this has always been resolved
by editing the post and minimizing the white space and carriage returns
that follow or precede one of the formatting tags.
Go here for the bug report on the BlogEngine.Net project site
Jimmy