Issue in adding x-cq-linkchecker attribute to anchor tag

Hi all,

I have a requirement to add x-cq-linkchecker attribute to an anchor tag conditionally (basically on the basis of the option selected by author in dialog). I am aware that to add this attribute in /apps/cq/xssprotection/config.xml. Following is the xml entry in anchor tag:
<attribute name="x-cq-linkchecker">
<regexp-list>
<regexp name="anything"/>
</regexp-list>
</attribute>

The issue is that despite adding it to the config file in /apps/cq/xssprotection, I am still not able to use it in the anchor tag. Following is an example of how I have added it to the anchor tag:
<a
x-cq-linkchecker="${button.skipLinkChecker ? 'skip' : ''}"> Test anchor link </a>

This is what I see on page:
<a>Test anchor link</a>

Note: I have checked that ${button.skipLinkChecker} contains a value and that there is no issue in this condition.

Thanks