@intertax , whereas I have no knowledge about the workings of your particular bank , the wire transfers that I have initiated from US to other countries have always worked and I suspect that if a bank cannot affect the transfer they will indeed come back to you to seek new instructions if that is required ( e.g. the receiving bank rejects because of account detail errors ). All IRS is trying to alert you on is that you cannot claim post mark privilege in computing interest and penalty ( if applicable ) i.e. it is the date of receipt in their account that will be used for all purposes including penalty and interest charges.
If you are still unsure , perhaps you should consult (a) your bank and (b) the IRS section at the nearest US consulate ( most consulate/embassy have IRS section especially in countries with sizable Expats ( military or otherwise)
