Option to select an import statement

In a customised stylesheet, I have two options to import a chunking
    stylesheet for HTML chunking:

    

        <xsl:import
    href="" class="moz-txt-link-rfc2396E" href="file:///c:/DocBook_xslns1-76/xhtml-1_1/onechunk.xsl">"file:///c:/DocBook_xslns1-76/xhtml-1_1/onechunk.xsl" />

        <xsl:import
    href="" class="moz-txt-link-rfc2396E" href="file:///c:/DocBook_xslns1-76/xhtml-1_1/chunkfast.xsl">"file:///c:/DocBook_xslns1-76/xhtml-1_1/chunkfast.xsl" />

    

    How can I give users the option of selecting one import statement or
    the other, by using some sort of selection variable?

    I know I can comment out either import statement, but is there a
    slicker way to do this with a simple "1" or "0" selection? 

    

    
-- 

      Dave Gardiner