So, you probably already know.
You need two of three keys to sign a transaction with Bitgo.
You have one key, Bitgo has one key, and an organization called Keyternal has a key.
The problem is Bitgo and Keyternal do not want to hand over your wallet keys.
This has to do with Bitgo being more of a BTC vault, rather than a BTC wallet. WIth a wallet, you can typically get the keys and start a new wallet with some other wallet client/software. You can also typically sign transactions. Bitgo has not implemented that yet,
I will email Keyternal and explain the situation. Ultimately, I see about three end-case-scenarios. Due to never being able to sign the XEL donation/ICO transaction with two of three keys, you lose your $XEL. Next scenario, you sign a transaction and keyternal signs a transaction. This second scenario is very hard. Tracking down the exact transaction to sign with a multi-sig wallet involves a lot of testing, as far as I know. To get keyternal to sign the right transaction would be very hard. The third and most promising scenario is using the Bitgo API to sign the transaction. However, I am not completely positive of the functionality here, especially with one key being held by Keyternal. From what I read a couple of months ago, it may be possible.
I suppose a fourth scenario is that Bitgo will eventually create the transaction signing functionality. I am sure it is on their backlog, however hard to implement.
I will email keyternal tomorrow and see what exactly you can do with the public key that is on your keycard and links to the second private key that you need and they hold. However, they are pretty clear on their site/docs that they don't ever release the key from cold storage.