fortunately about the time all of this started happening, I ran wireshark and grabbed all of the data that is used for the registration process. Since the registration was over http only, it was super simple. Its a small xml that looks like this (where filling in the val's with the correct val's is required
<X10Register>
<RegRequest ver="1" success="1">
<FailureReason val=""/>
<ActivationKey len="40" val="{key}"/>
<RegistrationKey len="40" val="{regkey}"/>
<CheckKey len="40" val="{checkkey}"/>
<UserKey len="40" val="{userkey}"/>
<UserName len="11" val="{key}"/>
<ProductID val="0x000F00010320201F"/>
<CurrentTime val="139560429700000000"/>
<ValidStart val="0"/>
<ValidEnd val="0x7FFFFFFFFFFFFFFF"/>
</RegRequest>
</X10Register>
You would also need to set your hosts file to point to the server where such an application was listening.
I could see why its a bit troublesome for the new company if they don't have the customer database with all of the registration keys. Interesting enough I found that there are a variety of combinations you can use for the values that seem to work. But unfortunately I don't want to share due to piracy concerns and although I truly feel bad for those who bought hardware and can't use it, this is a well-fed lawyer country.
With that said, I personally have abandoned the ActiveHome Pro software and run MOCHAD on my raspberry pi. My use of x10 is phasing out anyhow and I have been going with more reliable solutions such as zwave and zigbee. I bought my zwave wall switches on ebay and they were cheaper than their x10 equivalent and offer so much more capability. That's not always the case, but their are good deals every once in a while.