Translate HTML tags into BiBTeX

[Steffen Ganschow]

I'm using tellico to manage my literature collection und use html tags 
extensively to format the output on the screen, e.g. indices in formulas etc. 
I understand that when exporting to BiBTeX special characters are translated 
according to the 'bibtex-translation.xml' shipped with tellico. But how to 
translate tags like <sub> ... </sub>? Is there a way to do this in a smart 
way like with the special characters? 
Steffen