Remove elements from speedbar-supported-extension-expressions

[Heime]

I want to have a function to remove elements from 
speedbar-supported-extension-expressions

What is a robust way to do it?  

If I do

C-h v speedbar-supported-extension-expressions

and pick up the entry in the way it is printed, would it be remaved if 
one just copies the entry?

Suppose the printed value is

(".[ch]\\(\\+\\+\\|pp\\|c\\|h\\|xx\\)?" ".tex\\(i\\(nfo\\)?\\)?" ".el"
 ".emacs" ".l" ".lsp" ".p" ".java" ".js" ".f\\(90\\|77\\|or\\)?"
 ".ad[abs]" ".p[lm]" ".tcl" ".m" ".scm" ".pm" ".py" ".g" ".s?html"
 ".ma?k" "[Mm]akefile\\(\\.in\\)?")
  
and match using 

   ".[ch]\\(\\+\\+\\|pp\\|c\\|h\\|xx\\)?"

to remove that entry.

Or is- it more robust to remove the entry by its position in the list?