Nordstrom uses categories like this:

<category>
<primary> Women </primary>
<secondary> Fragrance~~Perfume </secondary>
</category>

Suppose I want to get all their perfumes.

Searching for that exact string as category results in an error:

http://feed.linksynergy.com/productsearch?token=<removed>...&cat=" Fragrance~~Perfume "

<ErrorID>7186916</ErrorID>
<ErrorText>
Invalid characters in category. Invalid characters are as follows: , & = ? {} \ () [] - ; ~ | $ ! > * %
</ErrorText>

It seems linkshare allows advertisers to enter text as category that cannot be searched. Nordstrom isn't the only one doing this.

I tried using the parts of the category, but you get nothing back from either of these:

cat="perfume"
cat="fragrance"

Is there a way to search for products tagged with categories using this syntax?