Converting dotted decimal into IPv6 address

On Juniper routers they have vendor-specific traps for BGP and IPv6. One of the varbinds look like this:

jnxBgpM2PeerRemoteAddr.0.2.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.38.7.250.120.0.0.0.0.0.0.0.0.0.0.120.28= 38.7.250.1​20

this bit:

38.7.250.120.0.0.0.0.0.0.0.0.0.0.120.28

should get translated thus:

Which is the IPv6 address of a router.

Anyone suggest any incantation to convert from the dotted-decimal to the HEX version?

[note I'm almost certain the oidValue is being truncated to 4 bytes since the trap knows this is an IP address and assumes that it's an ipv4 addresses]

Thanks