Add phone number in contact card and utilize tel: protocol handler for invoking call capability using Jabber or Lync soft phone. The following number format (tel://+442075613215) already gets enabled for click to call on MM app/web.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/11_0/CJAB_BK_D657A25F_00_deployment-installation-guide-jabber-110/CJAB_BK_D657A25F_00_deployment-installation-guide-jabber-110_chapter_01111.html