I see 2 possibilities:
[list]
[li]Use the MSLUMatrixRead() function somewhere in your MSL code (typically somewhere in the initial section) to load data from a text file directly into your parameter vector[/li]
[li]Convert a text file with parameter values to a parameter library (.ParamLib.xml) using Tornado's tfile2paramlib command-line tool (not included in the standard WEST installer), and subsequently load that parameter library into the block containing the actual parameter vector through the Load button in WEST's Model Explorer window.[/li]
[/list]