php - Override PDF tax settings -

we override mage_tax_model_config have different tax settings specific customer groups. went except pdf documents.

we checked current customer group id $customer->getgroupid() $customer mage::helper('customer')->getcustomer();

why don't work on pdf documents? please see override class in detail:

public function displaysalespricesincltax($store = null) {     $customer = mage::helper('customer')->getcustomer();     if ($customer->getgroupid() > 1) {         return false;            } else {         return true;     } }  public function displaysalespricesexcltax($store = null) {     $customer = mage::helper('customer')->getcustomer();     if ($customer->getgroupid() > 1) {         return true;             } else {         return false;     } }