Good news for Conceptronic C54APRA and DLINK G604T ADSL modems
Latest firmware release with ADSL2+ functionality enables SNMPv2 features for this ADSL modem
Although the cfgmaker for MRTG does not retrieve all information correctly (no system information) the information for the dataspeed (traffic) is almost correct ;-) I used ifInOctets and IfOutoctets
So actually you can use this mrtg config script for the DSL line and WLAN or use the OID for ADSL in another config file.
Target[adsl]: 1.3.6.1.2.1.2.2.1.16.2&1.3.6.1.2.1.2.2.1.10.2:public@192.168.1.1
Enjoy.