Possible to concatenate shortcode?

Hi,

I’m trying the following:

echo do_shortcode('[wp_cart_display_product name="' . $itemTitle . '" price="' . $itemPrice . '"]');

But I get “Error! You must specify a product name in the shortcode”. It seems that it’s trying to interpret the shortcode before the string is concatenated. Is this technique possible? If not, is there a function for product display boxes that is equivalent to print_wp_cart_button_for_product?

Thanks for this amazing plugin btw. Cheers.

http://ww.wp.xz.cn/plugins/wordpress-simple-paypal-shopping-cart/