Try not to alter the connectors at the battery terminals. Get an equivalent sockets/plugs at the charger end to make a bridge [say JR/Futaba type male plugs] in your existing terminal type at the charging end and swiftly charge it without much hassle, after all the charge rate is just 2C and the connector can handle the charging power.
Soldering a XT60 male connector will probably become a challenge as it will be too fat to fit in the battery compartment and might damage the life battery/compartment in the process. The wolfpack lipo is little smaller than the this hk life battery yet, it is quite a challenge to pack the battery in the compartment while retaining its all original connectors.
PS: I am not an endorsing agent, but a humble request to purchase from local vendors/hobby shops to support them. Get the battery from RCB or any other LHS, the one I have got is sufficient to run maybe weeks/month without recharging it. RCB Link
here.