DPM 2012 does not detect SQL Server 2012 instance

I am trying to enable protection for SQL Server 2012 Developer Edition (SP1) with DPM 2012, but when I click on the SQL Server in "Available members" in the protection group, DPM enumerates only "All Shares", "All Volumes" and "System protection". I checked the VSS Writer service on the SQL server and it is started. Remote connections to the SQL sever are enabled and other servers use databases on it, so everything is fine with the SQL server. But I am not able to back it up since DPM does not show the instance at all and therefore I can't select the databases. No errors are reported, DPM just shows the above three items and "All SQL Servers" is not among them.

I ran diskshadow and list writers, this is the output:

DISKSHADOW> list writers status

Listing writer status information ...

        * WRITER "Task Scheduler Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {d61d61c8-d73a-4eee-8cdd-f6f9786b7124}
                - Writer instance ID: {1bddd48e-5052-49db-9b07-b96f96727e6b}

        * WRITER "VSS Metadata Store Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {75dfb225-e2e4-4d39-9ac9-ffaff65ddf06}
                - Writer instance ID: {088e7a7d-09a8-4cc6-a609-ad90e75ddc93}

        * WRITER "Performance Counters Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {0bada1de-01a9-4625-8278-69e735f39dd2}
                - Writer instance ID: {f0086dda-9efc-47c5-8eb6-a944c3d09381}

        * WRITER "System Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {e8132975-6f93-4464-a53e-1050253ae220}
                - Writer instance ID: {9685ff73-592a-4ea1-844d-117d28db3605}

        * WRITER "ASR Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {be000cbe-11fe-4426-9c58-531aa6355fc4}
                - Writer instance ID: {925cd5ff-d67e-4243-bf76-69be497f9a87}

        * WRITER "Shadow Copy Optimization Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
                - Writer instance ID: {461977cc-cea0-449c-b108-d15129ec7380}

        * WRITER "COM+ REGDB Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {542da469-d3e1-473c-9f4f-7847f01fc64f}
                - Writer instance ID: {75189190-3be1-4741-bafe-4829a7603463}

        * WRITER "Registry Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {afbab4a2-367d-4d15-a586-71dbb18f8485}
                - Writer instance ID: {639cd590-e6a9-48f9-a969-c195cc3fd03b}

        * WRITER "WMI Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
                - Writer instance ID: {f76a3e7b-504b-4690-8ee3-24be147d85b7}

        * WRITER "IIS Config Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {2a40fd15-dfca-4aa8-a654-1f8c654603f6}
                - Writer instance ID: {0071d81b-7e04-494e-83bd-079f340907bc}

        * WRITER "BITS Writer"
                - Status: 1 (VSS_WS_STABLE)
                - Writer failure code: 0x00000000 (S_OK)
                - Writer ID: {4969d978-be47-48b0-b100-f328f07ac1e0}
                - Writer instance ID: {4ea02d3c-ac54-490b-94ab-372d58e9a30b}

Number of writers listed: 11

Bit the service is there and running. Can I further investigate the issue? Thanks in advance.