Fails to create file (NotSupportedException) if appdomain in path contains colon

We have a RollingFileAppender in place with the following path:

<conversionPattern value=".\Logs\%appdomain.%date{yyyyMMdd}.%processid.log" />

Unfortunately this fails if the AppDomain contains a colon, because the path is no longer valid in that case.

To fully use this feature the AppDomain value should be stripped of invalid characters first, or replace those with an underline or something like that.

As a workaround: is there a way to replace characters? Something like:

%appdomain{:<>|}