dsaWithSHA1 signature by RSA 2048 key? [with openssl 1.0.1-snapshot]

gistfile1.txt

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 1 (0x1)
    Signature Algorithm: dsaWithSHA1
        Issuer: DC=org, DC=ruby-lang, CN=CA
        Validity
            Not Before: Dec  9 07:48:39 2011 GMT
            Not After : Dec  9 08:48:39 2011 GMT
        Subject: DC=org, DC=ruby-lang, CN=CA
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:b9:5f:61:b7:d2:7b:93:83:41:b3:7f:23:39:7b:
                    ef:4c:a6:3d:81:6f:27:2c:80:92:9e:8e:44:11:34:
                    75:72:e1:7b:8b:8a:4d:b3:d2:35:40:91:80:14:05:
                    f4:04:43:b8:29:bc:d7:9a:e3:af:7c:2a:43:dc:25:
                    3e:4a:5a:75:7a:77:a7:7f:3a:bf:b7:f7:bf:d4:84:
                    56:d3:09:09:50:95:05:42:28:27:e0:2b:6b:90:92:
                    fe:3f:4e:f2:c7:5f:14:8f:23:e5:05:76:fc:d4:0a:
                    44:98:00:79:9a:b2:55:4a:b5:a6:a9:b8:ec:d3:b2:
                    5b:b9:2e:10:40:61:97:2d:cf:92:bb:de:83:91:82:
                    a6:48:d5:63:06:22:f1:55:54:a9:c9:97:c0:63:78:
                    43:df:b7:7a:d2:e1:be:5f:cc:5d:5b:9b:fa:f0:99:
                    11:14:88:5d:1a:56:fa:24:bf:1f:96:57:ff:03:f6:
                    e5:37:07:49:3a:15:6b:f6:61:12:1e:1c:06:8f:07:
                    d2:79:30:cf:7d:df:19:2c:4d:36:ec:4e:65:c8:05:
                    57:f4:a6:58:71:4d:34:98:e5:fe:7d:dc:4e:4a:71:
                    aa:4b:ff:09:0d:18:74:10:f1:c3:2f:5e:51:70:98:
                    d5:d8:9e:af:66:33:db:d2:b3:98:18:3a:0c:70:7f:
                    bd:e3
                Exponent: 65537 (0x10001)
    Signature Algorithm: dsaWithSHA1
         4d:20:f4:dc:03:70:cf:b6:09:a1:c3:a4:ea:c2:41:83:a4:17:
         42:97:bc:d1:61:5d:25:98:99:5e:1b:46:e1:35:85:a5:fd:cc:
         7d:52:8f:65:b2:54:8c:d0:53:35:79:06:11:29:a6:5b:77:5c:
         36:81:99:a3:c6:55:75:81:e3:b6:a5:f3:68:cf:f0:b9:fa:99:
         74:3d:b1:88:d6:d6:69:1d:6c:43:e4:87:fc:c6:28:ad:0b:b4:
         58:f8:80:f8:88:94:13:20:a7:35:a6:06:f0:44:b4:ad:a4:a4:
         41:da:cb:e8:1a:ad:b6:e0:16:d8:a5:4b:06:f9:0c:de:6c:03:
         02:ba:5f:2e:87:38:ad:28:87:4c:93:b1:df:9c:69:f7:8e:50:
         4e:4d:bd:0c:73:65:3f:2b:ff:45:08:10:6b:f2:82:bb:ea:b6:
         58:6f:df:b0:9f:e1:55:ae:a4:6a:92:44:f7:c1:66:08:df:1a:
         6f:57:25:2e:51:bc:14:7c:c6:94:d3:e0:38:e8:58:56:cc:0c:
         98:75:e0:7d:69:da:ae:01:85:4c:c8:8c:4d:a7:44:9d:07:3f:
         fb:cf:a6:84:df:84:26:46:b6:ec:e6:dd:d7:ed:bf:08:45:43:
         82:58:e7:a9:eb:a0:8a:eb:b2:87:83:87:cc:7f:22:10:e0:1a:
         c5:1f:de:0e