I need some help with configuring SRX240 so that i can connect it as a client to a wired network which requires 802.1x EAP-MD5 authentication.
Can't SRX configure as an 802.1X supplicant?
To my knowledge the SRX platform cannot acts a 802.1x supplicant - and the features mentioned in the feature explorer, more relates to be the device enforcing supplicants connecting to the device: https://pathfinder.juniper.net/feature-explorer/select-platform.html?category=Security&typ=1#family=&pid=21900240&platform=SRX240&rel=12.3X48-D50&sid=837&stat=0.5928993614081215&swName=Junos+OS
So I think you have to find a workaround doing mac-based authentication or something similar in your wired network.
Please have a look at the following links for configuring SRX as a supplicant for dot1x.