almerika on "Hide buy button on products with specific tags WP E-commerce"

Hi.
Using WP E-commerce and Storefront Elegance theme for an online store. Trying to use a product tag as a condition to hide the buy-button and quantity update (on the single product page) for some products that only can be bought in the physical store (can't be shipped).

I've tried with css and it works fine but only on one specific product (post-1928) and not on a whole product tag.

Here's the css:
.post-1928.wpsc-product.type-wpsc-product .wpsc_quantity_update {
display: none;
}
.post-1928.wpsc-product.type-wpsc-product .productcol fieldset legend {
display: none;
}
.post-1928.wpsc-product.type-wpsc-product input.wpsc_buy_button {
display: none;
}

Here's the test-product: http://www.olsonsab.se/produkter/tillbehor/testprodukt-2/
Here's the product tag: http://www.olsonsab.se/etikett/demoex/

I've also tried a php code in the wpsc-single_product.php that hides the buy button if you're not logged in.

<?php if((get_option('hide_addtocart_button') == 0) && (is_user_logged_in()) && (get_option('addtocart_or_buynow') !='1')) : ?>

That example works good but I don't know what to put in instead to use the function for products with a specific tag. The tag is "demoex" (term-134).

Would really appreciate some help here. I've been searching for days.