Signature Base String: POST&http%3A%2F%2Frest.sandbox-immobilienscout24.de%2Frestapi%2Fsecurity%2Foauth%2Faccess_token%26oauth_consumer_key%3Dtestzugang-import-api-nodeKey%26oauth_nonce%3D4CD0FEFC910A6748B44CD072EFCE664E%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1386861684%26oauth_token%3Ded6bfad8-38eb-47c3-a641-bfc7ecb12b2c%26oauth_verifier%3DOdA8tZ%26oauth_version%3D1.0