Cannot user custom interface

[RacoonCityHost]

We made a number of changes to interface files (only graphics and the css file). However, when the panel gets new updates, we have to add graphics and css manualy again.
Is there any way to use a custom template so that our style won't be reset after panel updates?

[ksenya]

You need to add your css in BILLmanager -> Branding settings - >"HTML " "Heading". The code that you enter into this field will be added to HEAD of every page.
You can add custom icons via css as well