Configuration of hawtio log or VmLogAppender

Issue

• The configuration for pax logging in fuse org.ops4j.pax.logging.cfg contains the default entry

log4j.rootLogger=..., ..., osgi:VmLogAppender

• User understanding , the osgi:VmLogAppender is responsible for showing the log entries in hawtio. Is this correct?
• How to configure the logging such that hawtio only gets warn messages from our own applications (i.e. from loggers starting with 'com.mycompany') and info from camel / spring etc.
• BUT, applications should log on info level in a log file
• So user has something like logger.com.mycompany=INFO, logfileAppender
• To achieve that hawtio only gets warn messages, user usually would use a filter on the appender. How can user do that with osgi:VmLogAppender ?
• Is it possible to use XML instead of a properties file to configure logging?