The actual password hash is a number of bits. There's several ways how you can store random bits in a text field.
One of them is base64-encoded. That's the a4ayc/80/OGda4BO/1o/V0etpOqiLx1JwB5S3beHW0s= you see.
Another one is converting the bits to hexadecimal per byte and display those as decimal numbers, concatenated. That's the 6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b
see Hans' response
Assuming you control both start and end point, I'd advise you don't mix your custom hashes with Mendix passwords. Store the hashes yourself and match those with the input parameters in your webservice calls.