Unfortunately ASIO's license is not compatible with the jammr client's open source GPL license. Many open source projects are affected. For example, here is Audacity's explanation
This means ASIO versions of jammr are not expected unless Steinberg change their license.
The trend has been for soundcards to come with WDMKS drivers, which are supported by jammr and provide low-latency. ASIO is becoming less relevant since WDMKS is part of Windows and eliminates the need for ASIO. Are you sure you need ASIO and don't have WDMKS drivers for your soundcard?