Create stack - invalid slave bands (multiple none unique)

I was trying to stack many processed S1 images but keep getting invalid slave bands returned.

The input scenes have multiple bands but i only wish the stacked output to contain the Intensity_VV band.

In example below I have provided 4 inputs a master and 3 slaves so listed the slave band 3 times (have also tried with it in once and upper and lower case “I”).
Is it just a case of this function can only stack every band within a scene and you cannot select specific bands to stack? So subset should be used first which does work fine because then i can ignore the master and slave parameters entirely.
Or is the problem that the bands i wish to stack all have the same name?
Or am i doing something else wrong?

Any suggestions would be appreciated

SNAP7.0.4 (was going to wait until the first update before going to 8)

define the stack parameters

params = HashMap()
params.put(‘masterBands’, ‘band_1’)
params.put(‘sourceBands’, ‘Intensity_VV,Intensity_VV,Intensity_VV,’)
params.put(‘resamplingType’, ‘NEAREST_NEIGHBOUR’)
params.put(‘initialOffsetMethod’, ‘Product Geolocation’)
params.put(‘extent’, ‘Master’)

full error
RuntimeError: org.esa.snap.core.gpf.OperatorException: Operator ‘CreateStackOp’: Value for ‘Slave Bands’ is invalid: ‘Intensity_VV’

Just to add that i have now tried with SNAP 8 with no success. I have also used source_band.getNames() and passed the output to the “sourceBands” input as a comma separated set of string which it still doesn’t like.
Any input on what the input is supposed to look like for this parameter would be helpful as “-PsourceBands=<string,string,string,…> The list of source bands.” doesn’t work or i am interpreting this statement wrongly and you should identify the bands some other way than with their names.