Error loading multisig transaction with trezor wallet

[ulrichard]

This happens on the current master branch.
Tested with git#7933448ec7a3fd476ae5b3085421a16b378ed829
and I think git#b1b15f510cc1496a765ac75cafdccef4d2af2c94

With the multisig view-only wallet, I create a tx, and save it to file.
With the trezor wallet, I load the tx from the file, and get the following:

File "/home/richi/sourcecode/electrum/gui/qt/transaction_dialog.py", line 45, in show_transaction
d = TxDialog(tx, parent, desc, prompt_if_unsaved)
File "/home/richi/sourcecode/electrum/gui/qt/transaction_dialog.py", line 61, in init
self.tx.deserialize()
File "/home/richi/sourcecode/electrum/lib/transaction.py", line 513, in deserialize
d = deserialize(self.raw)
File "/home/richi/sourcecode/electrum/lib/transaction.py", line 432, in deserialize
d['inputs'] = list(parse_input(vds) for i in xrange(n_vin))
File "/home/richi/sourcecode/electrum/lib/transaction.py", line 432, in
d['inputs'] = list(parse_input(vds) for i in xrange(n_vin))
File "/home/richi/sourcecode/electrum/lib/transaction.py", line 411, in parse_input
parse_scriptSig(d, scriptSig)
File "/home/richi/sourcecode/electrum/lib/transaction.py", line 354, in parse_scriptSig
pubkeys = [xpubkey_to_address(x)[0] for x in x_pubkeys]
File "/home/richi/sourcecode/electrum/lib/keystore.py", line 577, in xpubkey_to_address
pubkey = BIP32_KeyStore.derive_pubkey_from_xpub(xpub, s[0], s[1])
AttributeError: type object 'BIP32_KeyStore' has no attribute 'derive_pubkey_from_xpub'

[ecdsa]

thanks :)