Replicating multilevel analysis Mplus results

Since I am relatively unfamiliar with Mplus, The first step toward building a complicated model is to replicate some simpler results using statistical packages I have more knowledge on such Stata and R, then build it up piece by piece. 

As the effort to understand the multilevel mixture modeling capacity of Mplus, I have decided to use the Mplus sample data set, "ex10.1.dat", to try alternative model specifications in both Mplus, Stata and R. I am going to post a series of code and results. 

As the first step, I try this really simple Mplus code: 

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DATA: FILE IS ex10.1.dat;

VARIABLE: NAMES ARE y x1 x2 w class clus;

USEVARIABLES = y x1 x2;

WITHIN = x1 x2;

CLUSTER = clus;

ANALYSIS: TYPE = TWOLEVEL;

STARTS = 0;

MODEL:

%WITHIN%

y ON x1 x2;

%BETWEEN%

y ON ;

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which gives exactly the same results as the following Stata code: 

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xtreg y x1 x2, i(clus) mle

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