Are you able to see the trace ouput for other functions? There is a procedure within the Quick Start Guide which explains how to setup trace output over the HCI UART. I will talk to the SW team about the battery monitoring function and it's intended use.
Yes, I have been using the trace output extensively. I think I'm just not fully understanding how or what code can be overridden or how it needs to be re-compiled in order to change things. I will keep digging and look forward to some insight from your software team.
As it turns out, the code in the bleapp\app directory is the ROM code (not patched in). It's provided primarily as a reference and was not intended to be compiled in the manner described. What you can do is copy the necessry file[s] to the RAM\<your app> directory, and then include those in the makefile.inc and rename the entry functions to something new.
For example hello_sensor calls blebat_Init, you can change that to call _blebat_Init and then provide RAM code which will be doing something similar as what was done in the ROM version, but with your required modifications.