Is your custom ULS logging not appearing in the SharePoint ULS logs?
I have had the (sometimes torturous) pleasure of developing custom SharePoint solutions for a number of years now and one of the issues I encounter from time to time is when my custom ULS logging is not being written to the standard SharePoint ULS logs. I usually encounter this when most other developers don’t. This is primarily because I always build out my SharePoint development environments using several service accounts in an effort to replicate the target production environment as much as possible. Doing this allows me to catch and reproduce security related design and coding issues that would otherwise go undetected in my development environment, but are most certainly exposed in QA or Production. This logging issue (entries missing) is likely to occur when using a web application pool service account that differs from the farm account. This is simply a best practice that all developers should follow, but many don’t out of laziness.
So, to successfully log to the SharePoint ULS logs the application pool service account must be in the Performance Log Users group in Active Directory. This group is located in the Builtin folder in Active Directory Users and Computers. Any SharePoint service account that executes your custom logging will need this access.